What if deku had poison manipulation quirk

 

The world is not born equal. It was a harsh, immutable truth that Izuku Midoriya learned not at the age of four, but in the agonizing months leading up to it.

 

Before the purple haze, before the terrified screams, and before the heavy, suffocating scent of bitter almonds became a permanent fixture in his life, Izuku was just a boy who loved heroes. He loved the bright, primary colors of All Might’s costume. He loved the booming, thunderous laughter that chased away the darkness on the television screen. And more than anything, he loved the idea that anyone—no matter how small—could stand between danger and the innocent.

 

In those early days, the playground in Musutafu was a kingdom, and Katsuki Bakugo was its undisputed king. Katsuki had manifested his Quirk early. Explosions. Bright, loud, and inherently heroic. Every pop and crackle from Katsuki’s palms drew a crowd of awestruck peers and beaming adults. Izuku had been right there in the front row, his wide green eyes reflecting the flashes of caramel-scented fire.

 

"Wow, Kacchan!" Izuku would cheer, clapping his small hands together. "Your Quirk is amazing! You’re gonna be the best hero ever!"

 

"Obviously," Katsuki had smirked, crossing his arms over his chest, his red eyes gleaming with unshakeable confidence. "I’m gonna surpass All Might. And you’re gonna be right behind me, right, Deku? Once you get your Quirk."

 

"Right!" Izuku had beamed.

 

But the days bled into weeks, and the weeks into months. Four candles on a birthday cake were blown out. No Quirk. The anxiety began as a low hum in the back of Izuku’s mind. What if he was quirkless? The extra joint in the pinky toe—he had read about it on the hero forums his mother let him browse. The doctor's appointment was scheduled for next week to check his X-rays. Izuku was terrified. He was the last boy in his kindergarten class to manifest. The glances from the other children shifted from expectant to pitying, and Katsuki’s confident declarations began to take on a sharp, mocking edge.

 

Then came the afternoon in early spring. The cherry blossoms were just beginning to fall, dusting the local park in a layer of pale pink.

 

Izuku was sitting in the sandbox, painstakingly attempting to mold a replica of the U.A. High School building out of damp grains. A shadow fell over him. He looked up, squinting against the late afternoon sun, to see Tsubasa—a boy who had recently grown a pair of leathery, bat-like wings—looming over him alongside two other boys. Katsuki was a few yards away, kicking a soccer ball against a chain-link fence, pointedly ignoring them.

 

"Still playing in the dirt, Deku?" Tsubasa sneered, flexing his wings. The appendages cast long, monstrous shadows across Izuku’s carefully sculpted sand-tower. "Did you figure out your Quirk yet? Or are you really just an empty shell?"

 

"I-I'm going to the doctor next week!" Izuku stammered, his cheeks flushing with embarrassment. He defensively hovered his hands over his sandcastle. "My mom says I'm just a late bloomer. It’s coming."

 

"Yeah, right," one of Tsubasa's cronies, a boy with elongated, stretchy fingers, laughed. "My dad says people who don't get it by four are defective. You're broken, Deku."

 

"I'm not broken!" Izuku protested, his voice pitching higher. Tears pricked the corners of his eyes, but he aggressively blinked them away. Heroes didn't cry when villains taunted them. All Might would laugh it off. Izuku tried to force a smile, but his bottom lip trembled. "I'm gonna be a hero!"

 

Tsubasa’s expression darkened. The innocence of childhood cruelty was a fickle, volatile thing. It didn't take much to tip from teasing into violence. "A hero? You don't even have a power! You're just in the way!"

 

Without warning, Tsubasa stepped forward and kicked the sandcastle. The damp earth exploded, spraying grit into Izuku’s eyes and face. Izuku cried out, throwing his hands up to protect himself, but the momentum was already against him. Tsubasa shoved him hard in the chest.

 

Izuku tumbled backward, scraping his elbows against the rough concrete edge of the sandbox. A sharp sting flared up his arms. Panic, hot and blinding, seized his chest. He was scared. He felt backed into a corner, small, helpless, and completely at the mercy of boys who had weapons built into their very DNA.

 

Stop, Izuku thought, his breath hitching. Please stop.

 

Deep within his core, something clicked.

 

It didn't feel like the sudden ignition of a spark, the way Katsuki described his explosions. It wasn't a sudden rush of physical strength or a flexing of a new, phantom limb. It felt like a dam breaking open in his bloodstream. A sudden, nauseating wave of heat washed over Izuku’s entire body. His stomach churned violently, a phantom sickness rising in his throat. The pores on his forearms, palms, and neck suddenly felt uncomfortably open, weeping a strange, cold moisture.

 

Then came the smell.

 

It was overpowering. A sickly-sweet aroma, like rotting lilacs mixed with the metallic tang of battery acid.

 

"Hey, what are you doing?" Tsubasa asked, his voice suddenly losing its bravado.

 

Izuku opened his eyes. The world was tinted in a faint, sickly shade of violet. Pluming from Izuku’s skin, rising in thick, heavy wisps like dry ice, was a dense purple fog. It didn't dissipate into the wind; it clung to the ground, rolling over the edge of the sandbox like a creeping tide. Izuku inhaled, his chest heaving, and found that the gas felt cool and soothing in his lungs.

 

But not for Tsubasa.

 

Tsubasa took a step back, but he had already inhaled a lungful of the violet mist. The winged boy's eyes widened in sheer terror. He opened his mouth to speak, but only a wet, strangled gasp escaped his lips.

 

"Tsubasa?" the stretchy-fingered boy asked, taking a step back.

 

Tsubasa’s wings seized violently. His knees buckled. It was as if his strings had been cut. The boy collapsed into the sand like a sack of stones, his body completely rigid. His eyes darted around in absolute panic, locked in a state of horrific paralysis. He couldn't move his arms. He couldn't move his legs. Even the muscles in his jaw were locked tight. Only the shallow, rapid rise and fall of his chest indicated he was still breathing.

 

The playground fell dead silent. Even the distant sound of traffic seemed to mute itself.

 

Katsuki stopped kicking his soccer ball. He turned around, his red eyes widening as he took in the scene. The purple fog was already beginning to thin, dissolving into the air, but the damage was done. Izuku sat on the concrete, his small hands trembling, staring at the paralyzed boy in the sand.

 

"I-I..." Izuku whispered, looking down at his palms. They were coated in a faint, shimmering, oily residue. "I didn't... I didn't mean to..."

 

A scream tore through the park. It was Tsubasa’s mother. She had been sitting on a nearby bench, chatting with another parent. She sprinted across the grass, her face pale with terror.

 

"Tsubasa! Oh my god, Tsubasa!" She threw herself to her knees, reaching for her son. But the moment her hands brushed against the lingering oily residue on Tsubasa’s jacket, she yanked them back with a hiss. Her fingertips were red and blistering, as if she had touched a hot stove. She looked up at Izuku, her eyes wide, wild, and filled with a profound, instinctual horror.

 

"What did you do?!" she shrieked at the four-year-old boy. "What did you do to my son?!"

 

"I don't know!" Izuku wailed, tears finally spilling over his cheeks. The heat inside his body was becoming unbearable. His vision swam. A massive, crushing headache slammed into his temples, and a wave of severe nausea forced him to double over. He retched dryly, his small body convulsing.

 

Adults were swarming now. Cell phones were whipped out. Someone was yelling for an ambulance. Someone else was yelling for a hero.

 

Through the blur of his own tears and the sudden, spiking fever ravaging his tiny body, Izuku caught a glimpse of Katsuki. The blond boy wasn't running forward to see what was wrong. He wasn't yelling for everyone to calm down. Katsuki was taking a slow, deliberate step backward. For the first time in his life, Katsuki Bakugo was looking at Izuku Midoriya with fear.

 

The sirens wailed in the distance, growing louder, drowning out the sound of Izuku’s crying. The boy who wanted to be a hero had just put someone in the hospital.

 

 

 

The sterile, blinding white of the hospital room offered no comfort. The smell of bleach and antiseptic was sharp, but Izuku could still smell the phantom scent of bitter almonds clinging to the back of his throat.

 

He was sitting on an examination table, swinging his short legs, wrapped in a thick blanket. Despite the warm temperature of the room, he was shivering violently. His mother, Inko Midoriya, sat beside him. Her face was pale, her eyes red from crying, and her hands gripped Izuku’s small, un-gloved hand so tightly it almost hurt. She hadn't let go of him since she arrived at the hospital, frantically apologizing to the police officers, the nurses, and Tsubasa’s mother in the waiting room.

 

The door clicked open, and Dr. Garaki stepped in. He was a round man with bushy a mustache, thick goggles that obscured his eyes, and a clipboard clutched tightly to his chest. He looked over the rim of his glasses at Izuku, his expression unreadable, calculating.

 

"Well, Mrs. Midoriya," the doctor said, his voice a low gravelly hum as he closed the door behind him. "The boy who was brought in... Tsubasa. He is going to be fine. The paralysis is already beginning to metabolize out of his system. He should have full motor function back by tomorrow morning. There will be no permanent nerve damage."

 

Inko let out a shuddering breath, her shoulders dropping as a massive weight was lifted from her. "Oh, thank goodness. Thank God. I am so, so sorry, Doctor. We had no idea. Izuku has never... he's a good boy. He would never hurt anyone on purpose."

 

"I am aware," the doctor said dryly, flipping a page on his clipboard. "Quirk awakenings are often volatile. Particularly when they manifest during states of heightened emotional distress. A survival mechanism. However, young Izuku’s case is... exceptionally rare. And, quite frankly, highly dangerous."

 

Izuku shrank back against his mother's side. The word 'dangerous' hung in the air like a physical weight.

 

"We ran extensive blood panels, analyzed the residue on the other boy's clothing, and took a look at Izuku’s sweat glands," the doctor continued, tapping a pen against the paper. "Izuku possesses a Mutant-Emitter hybrid Quirk. I have tentatively categorized it as Toxic Synthesis."

 

"Toxic... Synthesis?" Inko repeated, stumbling over the words.

 

"In simple terms, Mrs. Midoriya, your son is a walking biological hazard," the doctor said bluntly. He didn't seem to care that a four-year-old was listening. "His body functions as a highly advanced chemical refinery. His apocrine glands—the glands that produce sweat—as well as his salivary glands and the very lining of his lungs, have mutated. He is capable of synthesizing, secreting, and manipulating various forms of complex toxins."

 

Dr. Garaki pulled out a laminated diagram of a human body, pointing to various organ systems. "The purple gas he released today was a localized, aerosolized neurotoxin. It blocked the neurotransmitters in the victim's nervous system, causing instantaneous temporary paralysis. But that is only what his body produced under the specific stress of being attacked. Theoretically, as he grows and his Quirk develops, his body will be capable of producing a vast array of chemicals. Corrosives, paralytics, hallucinogens, sedatives... perhaps even lethal venoms."

 

Inko gasped, her hand flying to cover her mouth. "Lethal?"

 

Izuku’s eyes widened. Lethal. Deadly. Villains kill people. Heroes save them. "I don't want to kill anyone!" Izuku cried out, his voice cracking. "I'm a hero! I'm gonna be a hero like All Might!"

 

The doctor looked at Izuku, a faint, almost pitying smirk twitching beneath his mustache. "A noble goal, young man. But you must understand the nature of your biology. Your body is designed to harm. You are immune to your own toxins, of course. Your white blood cells act as universal antibodies. However, the production of these chemicals requires immense caloric energy and water. That is why you experienced a severe fever, dehydration, and vomiting after the incident. Overusing your Quirk could literally boil you alive from the inside out."

 

The doctor turned back to Inko, his tone dropping to a serious, hushed register. "Mrs. Midoriya. I am legally obligated to register his Quirk in the national database. Given the nature of Toxic Synthesis, he will be placed on a Class-A Hazard watchlist. He cannot be allowed to lose his temper. If he secretes an acidic compound by accident, he could melt a child's face off. If he exhales a potent enough neurotoxin in a closed room, he could kill a dozen people before they even hit the floor. He requires rigorous discipline. I strongly recommend specialized counseling, and... perhaps a discussion about adjusting his career aspirations."

 

The words struck Izuku like physical blows. Every syllable shattered a piece of his innocent dream.

 

Hazard watchlist. Melt a child's face off. Kill a dozen people. Adjust his career aspirations.

 

He wasn't a hero in the eyes of this doctor. He wasn't a hero to Tsubasa. He was a monster. He was a villain waiting to happen.

 

Inko pulled Izuku tightly against her chest, wrapping both arms around him as if she could shield him from the doctor's words. "My son is not a hazard," she said, her voice shaking but laced with a fierce, maternal steel Izuku had rarely heard. "He is a four-year-old boy. We will manage this. We will learn control. Thank you, Doctor."

 

She stood up, scooped Izuku into her arms, and carried him out of the room. Izuku buried his face in his mother's shoulder. He didn't cry. The tears had burned up in the heat of his fever. Instead, a deep, hollow silence settled into his chest. He closed his eyes and tried not to breathe, terrified that if he exhaled too hard, he might poison the mother who was carrying him.

 

 

 

The news of the incident spread through the neighborhood like wildfire. In a society governed by Quirks, word of mouth was the fastest news network in the world. By the time Izuku returned to kindergarten a week later, the entire social ecosystem of his world had been violently upended and rewritten.

 

It started at the school gates.

 

Inko had walked him to school, holding his hand. Before they left the house, she had presented him with a pair of soft, white cotton gloves. “Just to be safe, Izuku,” she had said, offering a strained, teary smile. “They look like magician’s gloves, don’t they? Or like the gloves pro heroes wear so they don't leave fingerprints!”

 

Izuku had accepted them silently. They felt restrictive, hot, and alien on his small hands. He also wore a thick medical mask over his nose and mouth. He looked less like a hero in training and more like a quarantine patient.

 

As they approached the gates, the chatter among the parents instantly died down. It was as if someone had hit a mute button on the world. Mothers pulled their children closer to their legs. Fathers leaned down, whispering urgently into their kids' ears while shooting side-long, venomous glares at Inko and Izuku.

 

“That’s him. The Midoriya boy.”

“I heard he almost killed the Tsubasa kid. Poor boy was paralyzed for hours.”

“Why would they let a biological weapon into a public school? He belongs in a containment facility.”

“It’s a villain’s Quirk. Mark my words. You can’t have power like that and stay sane.”

 

Izuku gripped his mother's hand tighter. He could hear them. He knew Inko could hear them too, by the way her jaw clenched and her eyes stared rigidly ahead. She knelt down in front of him at the gate, ignoring the stares.

 

"Izuku, look at me," she said gently, adjusting his mask. "You are a good boy. You are kind, and smart, and you have a wonderful heart. Do not let anyone tell you otherwise. Keep your gloves on. Don't get into fights. And remember... I love you."

 

"I love you too, Mom," Izuku mumbled through the thick fabric of the mask.

 

He walked into the classroom alone. The moment he stepped through the sliding door, the noise inside vanished. Thirty pairs of eyes locked onto him. The teacher, a young woman who had always praised Izuku’s crayon drawings, gave him a nervous, tight-lipped smile and gestured to a desk that had been moved.

 

His desk was no longer in the middle of the room. It had been pushed all the way to the back corner, near the open window, isolated by a three-foot radius of empty space from the nearest student.

 

Izuku kept his head down, clutching the straps of his yellow backpack, and walked to his new island of isolation. He sat down. Nobody spoke to him. When it was time for free play, the children actively avoided his corner of the room. If he walked toward the bookshelf, the kids reading on the rug would scatter.

 

But the hardest part wasn't the isolation from the extras. It was Katsuki.

 

During recess, Izuku walked out into the courtyard. He saw Katsuki standing near the jungle gym, surrounded by his usual lackeys. Tsubasa wasn't there; he had been transferred to a different school by his terrified parents.

 

Izuku took a deep breath. His chest felt tight. He missed his friend. He missed the confident, fiery boy who always told him they were going to be heroes together. Izuku took a step forward, raising a white-gloved hand.

 

"K-Kacchan?" Izuku called out, his voice muffled by the mask.

 

Katsuki turned around. The moment his red eyes landed on Izuku, his expression twisted into a snarl. It wasn't the arrogant, playful superiority he usually wore. It was defensive. It was the look of an animal encountering a predator it didn't know how to fight. Explosions could blast away rocks, melt steel, and intimidate villains. But how do you punch a poisonous gas? How do you blow up a chemical that seeps into your skin and stops your heart? Katsuki was smart enough to understand the implications of Izuku’s Quirk.

 

"Stay away from me, Deku," Katsuki barked, his palms popping with warning sparks.

 

Izuku flinched, stopping in his tracks. "Kacchan... I just wanted to play. We said we were going to play heroes today..."

 

"We aren't playing anything!" Katsuki yelled, taking a step forward to put himself between Izuku and his lackeys, though he clearly didn't want to get too close. "I don't play with villains! You're a Walking Hazard, Deku! You're a freak!"

 

The words cut through the spring air like a physical blade.

 

"I'm not a villain!" Izuku yelled back, his fists clenching at his sides. The sudden spike of emotion caused his heart rate to accelerate. Automatically, his Quirk responded to his distress. A faint, localized hissing sound emerged from his forearms. A thin wisp of pale green gas began to seep through the fabric of his long sleeves. It smelled of sulfur and burning plastic.

 

The kids behind Katsuki screamed and scrambled backward. Katsuki himself flinched, his eyes darting to the green smoke, his sparks fizzling out in sheer panic. "Get away! Look at you! You're leaking poison right now! You're gonna kill us!"

 

Izuku gasped, looking down at his arms. He squeezed his eyes shut, forcing himself to take a deep, shaky breath, desperately trying to calm his racing heart. Stop. Stop. Stop. He willed the heat in his blood to cool down. Slowly, the green smoke dissipated, leaving only the acrid smell behind.

 

When he opened his eyes, he was completely alone. Even Katsuki had retreated to the other side of the playground, watching him from a safe distance like he was a ticking bomb.

 

Izuku didn't cry. He realized, with the crushing, heavy clarity that only trauma can force onto a child, that crying wouldn't fix this. Crying made his heart rate spike. Spiking his heart rate made the poison leak. To survive, to keep others safe, he had to be calm. He had to be in control.

 

He walked over to a solitary swing, sat down, and looked at his white-gloved hands.

 

A villain's Quirk.

 

Was it? If a Quirk was just a physical trait, like having blonde hair or an extra toe, how could it be evil? Knives were used by villains to hurt people, but chefs used them to make dinner. Doctors used scalpels to save lives. It was just a tool.

 

Izuku looked up at the sky. He could still be a hero. He would be a hero. He just couldn't be a hero like All Might. All Might smashed things. All Might hit things with overwhelming, blunt-force trauma. If Izuku lost control and smashed things, people would die.

 

If he was going to be a hero, he had to be perfect. He had to understand exactly what he was doing. No accidents. No collateral damage. No casualties.

 

 

 

That evening, Izuku sat in front of the family computer. The room was dark, illuminated only by the glow of the monitor. The famous video was queued up on the screen—the disaster in the Philippines. The burning city, the collapsing bridges, and the booming, fearless laugh of the Symbol of Peace.

 

“Fear not, citizens! Hope has arrived. Because I am here!”

 

Usually, Izuku would be bouncing in his chair, clutching his All Might action figure, mimicking the pose. Tonight, the action figure sat untouched on the desk. Izuku watched the video with a blank, serious expression. He watched the way All Might’s Detroit Smash altered the weather pressure, blowing away the debris.

 

A shockwave like that, Izuku thought, his four-year-old brain working in overdrive, would scatter a poisonous gas over a three-mile radius. It would affect civilians. A power like that doesn't work for me.

 

He closed the browser tab.

 

He opened a new search window. His small, gloved fingers clumsily navigated the keyboard. He didn't know how to spell very well yet, but he knew enough phonetics to get the search engine to understand him.

 

He typed: H-o-w  d-o  p-o-i-s-o-n-s  w-o-r-k ?

 

He hit enter. Millions of results flooded the screen. Articles on venomous snakes, poisonous frogs, industrial chemicals, plant biology, and human anatomy.

 

The door to the study creaked open. Inko peeked inside, carrying a small tray with a cup of tea and some crackers. Her eyes were red, indicating she had been crying again in the kitchen.

 

"Izuku, sweetie?" she asked softly. "What are you watching? Do you want to watch the All Might video together before bed?"

 

Izuku turned around in the swivel chair. The blue light from the monitor reflected off the plastic rim of his medical mask. He looked at his mother. He didn't ask her if he could still be a hero. He didn't ask for her permission or her reassurance, because he knew she couldn't give him the answer he needed. She loved him, but she was terrified of him. Everyone was.

 

"No, Mom," Izuku said, his voice quiet but incredibly steady. "I need to study."

 

Inko blinked, walking over and looking at the screen. She saw the diagrams of snake venom breaking down blood cells. She saw the complex, colorful structures of chemical compounds. "Study? Izuku, this is... this is very advanced. What is all this?"

 

"The doctor said I need to understand my biology," Izuku said, turning back to the screen. He pulled out a fresh, blank notebook from his desk drawer. It was supposed to be his 'Hero Analysis for the Future Vol. 1'. Instead, he opened it to the first page, picked up a pen, and meticulously began to copy a diagram of a human nervous system. "If my body makes poison, I need to know every single poison in the world. I need to know how they work, how fast they work, and how to stop them. I need to know how to make antidotes."

 

Inko stared at her small son, a chill running down her spine. The innocent, carefree boy who bounded around the house in an All Might onesie was gone, replaced by this intense, hyper-focused child scribbling chemical formulas he couldn't possibly comprehend yet.

 

"Izuku... why?" she asked, her voice breaking.

 

Izuku stopped writing. He looked down at his gloved hands. "Because... Kacchan called me a walking hazard. He's right. If I don't know what I'm doing, I could hurt someone. But if I know everything... if I have perfect control... then I can use it to stop bad guys without hurting them permanently. I can put them to sleep. I can paralyze them just enough to put handcuffs on them. I can be a hero who never causes collateral damage."

 

He looked back up at Inko, his green eyes burning with a relentless, fierce determination that frankly terrified her. "I'm going to prove them wrong, Mom. I'm going to show everyone that poison doesn't have to kill."

 

 

 

Ten Years Later.

 

The alarm clock blared a sharp, electronic screech at exactly 4:30 AM.

 

A hand shot out from beneath the dark green comforter and slammed the snooze button. The hand was wrapped in black, skintight, compression fabric—a specialized microfiber designed to contain moisture and gas.

 

Fourteen-year-old Izuku Midoriya sat up in bed, rubbing his eyes. His room was devoid of the bright, primary colors of typical teenage hero fans. The All Might posters that once plastered the walls had long since been replaced by sprawling, hand-drawn diagrams of complex organic chemistry, periodic tables, and detailed physiological charts of the human endocrine and nervous systems. A massive bookshelf dominated one wall, bowing under the weight of college-level medical textbooks, toxicology journals, and encyclopedias of botanical venoms.

 

Izuku swung his legs over the side of the bed. He was not the small, scrawny kid who cowered in the sandbox. Ten years of rigorous, paranoid self-discipline had forged him into something completely different. He was lean, corded with wiry muscle built not for overwhelming power, but for speed, agility, and endurance.

 

He walked over to his mirror. He stripped off his sleep-shirt, looking at his reflection. His skin was pale, almost translucent in places, a side-effect of his body constantly diverting resources to maintain his volatile internal chemistry. He touched his chest. Beneath his ribs, his body was a cauldron. He could feel it. A low, constant simmer. He had spent a decade mastering his own biochemistry. By heavily altering his diet—consuming hyper-specific ratios of alkaline foods, acidic compounds, and massive amounts of water—he had learned to manually categorize and store different toxins in specific glands across his body.

 

Right forearm: Fast-acting somniferous gas (Sleep agent). Requires three deep breaths to synthesize. Exhaustion rate: low.

Left palm: Concentrated formic acid analog (Corrosive). Requires heavy alkaline intake the night before. Burn rate: high. Risk of dehydration: extreme.

Salivary glands: Tetrodotoxin variant (Paralytic venom). Requires zero-sugar diet for 48 hours to prevent premature breakdown. Risk to self: fever.

 

Izuku reached to his bedside table and strapped on his custom-fitted, industrial-grade respiratory mask. It covered the lower half of his face, equipped with twin carbon-filter cartridges. It wasn't just to protect others from him; it was to protect him from accidentally inhaling civilian-grade chemicals that could negatively react with his internal synthesizer.

 

He pulled on his custom gloves—black leather with specialized, dial-controlled release valves at the knuckles and palms, allowing him to vent gases or secrete liquids with pinpoint precision.

 

He grabbed his backpack, slinging it over his shoulder. Inside were his notebooks. He was currently on Biochemical Hero Analysis Vol. 13. It contained meticulously calculated dosages required to incapacitate every registered Pro Hero and villain he had ever seen on the news, factored by their height, weight, and Quirk-mutated metabolisms.

 

He walked quietly into the kitchen. Inko had left for an early shift at the hospital. She had left a note on the counter next to a massive, two-liter hydro-flask of water infused with electrolytes and a plate of plain, unsalted steamed chicken and broccoli.

 

Good luck at school today, sweetie. I love you! – Mom.

 

Izuku smiled beneath his mask. He quickly ate his strict, joyless breakfast, necessary fuel for the chemical factory inside him, and chugged half the hydro-flask. Hydration was life. If he used his Quirk while dehydrated, his body would cannibalize the moisture in his own blood, leading to immediate heatstroke.

 

He left the apartment, stepping out into the cool morning air of Musutafu. The streets were quiet. He preferred the early mornings. Fewer people. Fewer chances for accidents.

 

As he walked the familiar route to Aldera Junior High, his mind was already calculating. Today was the day they were supposed to submit their high school career forms. He knew exactly what he was writing down. U.A. High School. The pinnacle of hero education.

 

The societal stigma hadn't faded over the last ten years. If anything, it had solidified. Teachers graded him harshly, refusing to take papers directly from his hands. Classmates gave him a wide berth in the hallways, whispering behind their hands about the "Toxic Kid." Katsuki Bakugo had spent the entire decade making it his personal mission to remind Izuku that a villain's power had no place in a hero's world. Katsuki was louder, more aggressive, and vastly more powerful now, his explosions capable of shattering concrete.

 

But Izuku wasn't afraid of Katsuki anymore. Not really.

 

Fear was an unpredictable emotion. Unpredictable emotions led to lack of control. And Izuku Midoriya was the absolute master of control.

 

He turned a corner, approaching the train station, when the sudden sound of shattering glass and a booming, guttural roar shattered the morning peace. A massive shadow eclipsed the rising sun.

 

Izuku stopped. He looked up.

 

A villain—a towering monstrosity with skin made of jagged rock and concrete—had just smashed through the front window of a jewelry store across the street. The alarms were blaring. The villain hefted a massive sack of stolen goods, laughing as he swiped a massive, stone-crusted arm, shattering a nearby streetlight.

 

Civilians were screaming, scattering in all directions.

 

"Get out of my way!" the villain roared, his voice sounding like grinding tectonic plates. "First hero that shows up gets crushed into gravel!"

 

Izuku stood frozen on the sidewalk. He looked around. No heroes. The local patrol route usually didn't cover this intersection for another twenty minutes. Kamui Woods was likely dealing with the morning rush hour traffic disputes, and Mt. Lady was strictly downtown.

 

The villain took a step forward, his massive foot crushing a parked bicycle. He raised his fist, preparing to smash a car that was blocking his escape path. There was a woman inside the car, frozen in terror, frantically trying to unbuckle her seatbelt.

 

Izuku’s mind raced. Villain. Rock mutation. Heavy armor. Blunt force attacks will be ineffective. Skin is likely impenetrable to standard injections or dermal-absorption toxins. Respiration? He's yelling, meaning he has functioning lungs. He needs oxygen. Aerosolized attack is the optimal route.

 

"Hey!"

 

The word left Izuku's mouth before he could consciously process the decision.

 

The rock villain paused, turning his massive, craggy head. His glowing yellow eyes zeroed in on the scrawny, green-haired middle schooler standing on the sidewalk, wearing an industrial gas mask and black gloves.

 

"Huh?" the villain grunted. "What are you supposed to be, kid? You lost your way to a biohazard convention? Scram before I make a smear out of you."

 

Izuku didn't run. He didn't flinch.

 

Instead, he reached up with his left hand and pressed the release latch on his respiratory mask. The mask hissed, unsealing from his face. He let it drop, hanging loosely around his neck.

 

He took a slow, deep breath, expanding his lungs to maximum capacity. He felt the familiar, burning heat ignite in his core. His heart rate elevated perfectly to 130 beats per minute—the exact threshold required to trigger his thoracic synthesizer glands.

 

"I said scram!" the villain roared, raising a massive stone fist and charging straight at Izuku. The ground shook with every step.

 

Izuku locked his eyes onto the villain's mouth. He didn't need to destroy the villain. He didn't need to shatter his armor. He just needed to turn off the lights.

 

Compound synthesis: Thiopental sodium analogue mixed with a rapid-expansion volatile gas. Sleep agent.

 

As the villain closed the distance, looming over Izuku like a moving mountain, preparing to bring his fist down, Izuku opened his mouth and exhaled.

 

He didn't just breathe out. He pressurized the expulsion, utilizing a specialized breathing technique he had spent three years perfecting. A massive, concentrated stream of dense, heavy gray smoke erupted from his lips. It hit the villain dead in the face with the force of a fire hose.

 

The villain gasped in shock, inadvertently inhaling a massive volume of the gray gas.

 

"What the... cough... what is this..."

 

The villain's voice instantly slurred. His momentum carried him forward, but his knees buckled halfway through the stride. The thiopental analog hit his bloodstream through his lungs in less than two seconds. The massive stone fist dropped, missing Izuku by inches and cracking the pavement.

 

The villain's eyes rolled back in his head. He swayed like a felled redwood before crashing face-first onto the concrete, completely and totally unconscious. The sack of stolen jewelry clattered to the ground.

 

Silence descended on the street. The gray smoke dissipated quickly into the morning breeze, completely harmless in its diluted state.

 

Izuku stood over the massive, snoring rock villain. He reached up, calmly re-securing his respiratory mask over his face, locking the seal with a sharp click. He felt a wave of nausea and a spike in his body temperature. He reached into his backpack, pulled out his hydro-flask, and took a long, calculated drink to replenish the lost moisture.

 

The woman in the car slowly opened her door, staring at Izuku in sheer, unadulterated disbelief. "You... you took him down. With just a breath. Are you... are you a pro?"

 

Izuku looked at her. He didn't smile—she couldn't have seen it beneath the mask anyway.

 

"No, ma'am," Izuku said, his voice slightly muffled, calm and polite. "I'm just a student. Please call the police. He'll be asleep for exactly forty-five minutes. Inform the paramedics not to administer any stimulants; it could cause a negative cardiac reaction with the sedative."

 

He turned and continued his walk toward the train station. He had a career form to turn in.

 

Let society call him a hazard. Let Katsuki call him a villain. Let the world fear his power. Izuku Midoriya was going to be the greatest hero the world had ever seen, and he was going to do it without shedding a single drop of blood.

 

He was the cure.

 

The human body is an engine, and like any engine, it requires the correct fuel to operate at peak efficiency. For fourteen-year-old Izuku Midoriya, his diet was less about nutrition and more about munitions.

 

He sat in his seat near the back of the third-year classroom at Aldera Junior High, a heavy, insulated water bottle resting on his desk. Every fifteen minutes, his digital watch vibrated silently against his wrist, prompting him to take a measured sip. Today's internal payload was highly acidic. For the past three days, he had consumed a strict diet of citrus, fermented vegetables, and high-sulfur proteins, carefully manipulating his blood’s pH levels. His body was currently synthesizing a potent, localized corrosive agent in his apocrine glands.

 

The low hum of the classroom washed over him. The teacher was droning on about future careers, holding a stack of printouts.

 

"Since you're all third years, it's time to start thinking seriously about your futures," the teacher said, though his tone lacked any real authority. He suddenly grinned, tossing the stack of papers into the air. "But who am I kidding? You're all aiming for the hero course, aren't you?"

 

The classroom erupted. Quirks flared to life—elongated limbs, minor illusions, hardened skin, and localized levitation. It was a chaotic display of genetic lottery winnings. Izuku didn't cheer. He didn't raise his hand. He kept his eyes locked on his notebook, his black-gloved fingers smoothly twirling a mechanical pencil. He breathed slowly through the carbon-filter mask strapped to his face, the steady hiss of his respirators the only sound he made.

 

"Yes, yes, you all have wonderful Quirks," the teacher chuckled, waving them down. "But remember, using your powers in school is against the rules! Now, let's see... Katsuki Bakugo, you're going for U.A. High, correct?"

 

The noise in the room instantly died.

 

Katsuki Bakugo leaned back in his chair, his feet kicked up onto his desk. He wore a uniform shirt with the top buttons popped, exuding an aura of absolute, volatile arrogance. "Don't lump me in with these background characters, teach," Katsuki scoffed, a confident smirk spreading across his face. "I'm not aiming for U.A. I've already aced the mock tests. I'm the only one here who has the stuff to surpass All Might. I'm going to be the number one hero, and I'll be the richest, most famous guy in the world!"

 

Murmurs of awe and irritation rippled through the class, but no one dared challenge him. Katsuki’s Quirk, Explosion, was undeniably powerful.

 

"Oh, Midoriya," the teacher added, looking down at his clipboard, his voice dropping a few octaves into a tone of nervous reluctance. "You're also applying for U.A., right?"

 

The silence that followed was heavy, suffocating, and loaded with a decade of prejudice.

 

Every head in the classroom turned toward the back corner. They looked at the boy in the black gloves and the heavy mask. They didn't see a hero-in-training. They saw a biohazard. They saw the kid who had paralyzed Tsubasa ten years ago.

 

"Deku."

 

Katsuki’s voice cut through the silence like a knife. He slowly lowered his feet from his desk, turning his head to glare at Izuku. The caramel scent of nitroglycerin began to permeate the air. Sparks crackled dangerously in his palms.

 

"You think you can stand in the same ring as me?" Katsuki sneered, standing up. He kicked his desk aside and marched down the aisle, his face twisted in a predatory scowl. "You think a villain with a poison gimmick can be a hero? You're a walking corpse, Deku. The moment you step into the exam, they'll lock you up in Tartarus where you belong."

 

Katsuki slammed his smoking hands onto Izuku’s desk. The wood instantly charred, the smell of burning lacquer filling the air. "Withdraw your application."

 

Izuku stopped twirling his pencil. He didn't flinch. He didn't cower. Over the years, he had realized that Katsuki’s rage was a chemical reaction of its own—loud, expansive, but ultimately predictable.

 

Izuku looked up, his green eyes utterly calm, reflecting the sparks from Katsuki’s hands. He reached up with a gloved hand and gently, almost clinically, tapped Katsuki’s wrist.

 

"Your heart rate is elevated, Kacchan," Izuku said, his voice slightly muffled but perfectly level. "Your apocrine sweat glands are overproducing nitroglycerin due to stress. If you detonate your hands at this proximity, the blowback will cause second-degree burns to your own forearms. Furthermore..."

 

Izuku deliberately slowed his breathing. He focused on the pores of his left forearm. He didn't release a cloud. He just let the ambient heat of his skin vaporize a microscopic fraction of the sulfur-compound resting in his sweat glands.

 

A sharp, acrid scent, like rotting eggs and battery acid, instantly hit Katsuki’s nose. The blonde boy choked, his eyes watering reflexively, and he stumbled back a step, covering his mouth.

 

"Furthermore," Izuku continued smoothly, picking up his water bottle, "the ignition of your sparks in an environment where I am actively venting a highly flammable sulfuric gas could result in a thermobaric explosion, taking out this entire classroom. So, I would appreciate it if you stepped back."

 

Katsuki stared at him, coughing, a mix of pure rage and instinctual apprehension in his red eyes. He hated Izuku. He hated that the crying, weak boy from the sandbox had turned into this cold, calculating machine who could paralyze him with a breath.

 

"You..." Katsuki growled, wiping his watering eyes. "You think you're so smart. You're just a freak. A freak who has to wear a muzzle."

 

Katsuki turned and stormed out of the classroom as the bell rang, ignoring the teacher's protests. The rest of the students quickly gathered their things and practically sprinted out the door, desperate to escape the faint, lingering smell of sulfur.

 

Izuku sighed, taking a long drink of water. He pulled out a small aerosol can of neutralizer spray and misted his desk, nullifying the scent. He wasn't a freak. He was just prepared.

 

 

 

The incident under the bridge happened an hour later.

 

Izuku was walking home, taking a detour through a shaded underpass to avoid the afternoon sun. Heat was his enemy; it accelerated his metabolism and made his toxin containment difficult. As he walked, he reviewed his notes on the physical entrance exam. U.A. historically used robotic proxies for their practical exams. His sleep gas, paralytics, and neurotoxins would be completely useless against inorganic metal. He needed a way to destroy robots. That was why he had been dieting for acidity.

 

A sickening, squelching sound echoed from the manhole cover behind him.

 

Izuku spun around, his hand instinctively dropping to the release valves on his gloves.

 

The manhole cover blew off, clattering against the concrete. From the dark depths of the sewer, a massive, undulating mass of dark green sludge erupted. It smelled like raw sewage and stagnant water. Two large, bulbous eyes and a jagged mouth floated within the viscous liquid.

 

"A medium-sized meat suit," the Sludge Villain gurgled, its voice wet and heavy. "Perfect. I need to hide, kid. Don't fight it. It'll only hurt for about forty-five seconds."

 

The sludge lunged, a tidal wave of suffocating muck.

 

Izuku’s reflexes, honed by years of intense gymnastics and evasion training, kicked in instantly. He didn't freeze. He dropped under the initial sweep of the sludge tendril, rolling smoothly across the concrete.

 

Target analysis, Izuku’s mind raced. Amorphous physiology. No skeletal structure. No visible respiratory system. It absorbs oxygen directly through its fluid mass. Standard gases will diffuse too slowly in a liquid medium.

 

The villain roared in frustration, whipping three more tendrils at Izuku. Izuku vaulted off the curved wall of the underpass, flipping over a strike. He landed in a crouch, dialing his right glove's valve to maximum output.

 

"Stop moving, you little brat!" the villain shrieked.

 

Izuku inhaled sharply and unleashed a concentrated burst of Tetrodotoxin-B—a paralytic venom—from his palm, aiming for the center of the mass. The purple liquid hit the sludge... and did absolutely nothing. It just diluted into the villain's massive volume.

 

Ineffective, Izuku noted clinically, dodging another strike that shattered a brick pillar. It has no centralized nervous system to paralyze. Blood-brain barrier is non-existent. I need to target the only solid matter.

 

Izuku’s eyes locked onto the villain's massive, floating eyeballs.

 

Before Izuku could change his chemical output, the manhole exploded again. A massive rush of wind, carrying the force of a localized hurricane, tore through the underpass.

 

"HAVE NO FEAR, CITIZEN!" a booming voice echoed, vibrating the very concrete beneath Izuku's feet. "BECAUSE I AM HERE!"

 

All Might.

 

The Symbol of Peace didn't even use his Quirk in a traditional sense. He simply drew back his impossibly massive fist and threw a punch at the air.

 

"TEXAS SMASH!"

 

The wind pressure was apocalyptic. The sludge villain didn't even have time to scream. The sheer aerodynamic force ripped the liquid apart, splattering it against the walls of the tunnel in a thousand harmless droplets. The wind knocked Izuku off his feet, sending him skidding backward.

 

When the dust cleared, All Might stood there, a towering paragon of muscle and bright colors, laughing heartily as he scooped the scattered sludge into two empty plastic soda bottles.

 

Izuku picked himself up, dusting off his uniform. He stared at the Number One hero. For a fleeting second, the four-year-old boy inside him wanted to run up, ask for an autograph, and ask the burning question: Can a boy with a villain's Quirk be a hero?

 

But Izuku crushed that urge. He had made a promise to himself a long time ago. He didn't need validation from a man whose power was the exact antithesis of his own. All Might solved problems by blowing them apart. Izuku had to solve them with surgical precision.

 

"WELL, YOUNG MAN, APOLOGIES FOR GETTING YOU CAUGHT UP IN MY JUSTICE!" All Might boomed, capping the bottles and sliding them into his pocket. "BUT THANKS TO YOU DISTRACTING HIM, I CAUGHT THE VILLAIN! I MUST BE OFF! PRO HEROES ARE CONSTANTLY BATTLING TIME AS WELL AS EVIL!"

 

"Understood. Thank you for your assistance, All Might," Izuku said politely, bowing at a perfect forty-five-degree angle. He didn't ask for an autograph. He just picked up his dropped notebook.

 

All Might blinked, clearly surprised by the lack of fanboy hysteria. He gave a hearty thumbs-up. "STAY SAFE, CITIZEN!" With a massive flex of his legs, All Might leaped into the air, disappearing into the sky like a launched missile.

 

Izuku watched him go. He pulled out his notebook and jotted down a quick observation: Sludge physiology negates nervous-system attacks. Fluid dynamics dilute liquid toxins. Note to self: research rapid-coagulating agents or extreme desiccants for liquid-based foes.

 

He closed the book and resumed his walk home. He had a chemistry test to study for.

 

 

 

Ten minutes later, the peace of the afternoon was shattered.

 

It started as a distant rumble, followed by the unmistakable, concussive THOOM of an explosion. A plume of black smoke rose into the sky a few blocks away in the Tatooin Shopping District.

 

Izuku’s heart rate spiked, but he forced it down with practiced breathing. Explosions. The scent of burning ozone and... caramel.

 

Kacchan.

 

Izuku broke into a sprint. He didn't run like a normal teenager. He moved with a low center of gravity, his footsteps silent, weaving through the gathering crowd of onlookers with fluid grace. When he reached the perimeter, he saw a wall of police tape and a line of Pro Heroes standing idly by.

 

Death Arms, Kamui Woods, Mt. Lady, and Backdraft.

 

Beyond them, the shopping arcade was burning. And in the center of the inferno was the Sludge Villain. All Might must have dropped the bottles.

 

The villain was massive now, having absorbed nearby water mains, and trapped within its gelatinous body was Katsuki Bakugo. The blonde boy was thrashing wildly, his face submerged in the muck, his hands desperately setting off massive explosions that only served to set the surrounding buildings on fire.

 

"It's no good!" Death Arms shouted, covering his face from the heat. "I can't get a grip on the fluid! My strength is useless!"

 

"My wood will just burn!" Kamui Woods gritted his teeth. "And Mt. Lady can't fit in a two-lane street!"

 

"We have to wait for a hero with a suitable Quirk!" a police officer yelled.

 

Izuku stood at the front of the crowd, his green eyes calculating processing a thousand variables a second.

 

The heroes are waiting. They are assessing risk rather than acting.

 

Izuku looked at Katsuki. The boy's eyes were rolling back. His explosions were getting weaker.

 

Physiological fact: The human brain begins to suffer irreversible tissue damage after four minutes without oxygen. Katsuki has been submerged for at least two. The explosions consume the ambient oxygen, accelerating his asphyxiation. The heroes are waiting for backup that is at least five minutes away.

 

Conclusion: Katsuki Bakugo will die in one hundred and twenty seconds.

 

Izuku’s backpack hit the pavement.

 

"Hey! Kid, stop!" a police officer screamed.

 

Izuku didn't just run. He moved with lethal, focused intent. He vaulted over the police barricade, planting his hands on the hood of a police cruiser and flipping forward to maintain his momentum.

 

"What is that idiot doing?!" Death Arms roared, reaching out to grab him.

 

Izuku ducked under the massive hero's arm, his boots sliding against the asphalt. The heat of the fire washed over him, causing the sweat under his suit to boil. He tapped the dial on his right glove, twisting it past the green and blue markers, snapping it firmly onto the red marker.

 

Dietary payload: Active. Formic-Hydrochloric analog. Highly corrosive. Danger to self: Extreme dehydration.

 

"DEKU?!" Katsuki’s muffled, gargled voice echoed from within the sludge.

 

"You again?!" the Sludge Villain roared, recognizing the green-haired boy and the mask. "I'm going to snap your neck!"

 

Three massive tendrils of sludge whipped toward Izuku like liquid steel cables.

 

Izuku didn't stop. He sprinted toward the nearest wall, leaping off the ground and planting his feet on the brick. He ran horizontally along the wall for three steps, completely bypassing the first two tendrils, which smashed into the pavement where he had just been. As gravity pulled him down, he twisted his body in mid-air, dodging the third tendril by mere inches.

 

He landed in a slide, directly at the base of the towering Sludge Villain.

 

"Die!" the villain shrieked, preparing to crush him from above.

 

Izuku looked up. He didn't look at the massive fluid body. He looked directly at the villain's right, bloodshot eye. The only solid membrane. The only vulnerable point.

 

Izuku raised his right hand. He didn't throw a punch. He extended his index and middle fingers, forming a rigid spear.

 

He triggered the valve on his fingertips. A microscopic jet of pale, yellowish liquid shot from the specialized nozzles in his glove, coating his fingers in a searing, highly concentrated acid.

 

With blinding speed, Izuku thrust his fingers forward. He didn't strike the eye head-on; he didn't want to permanently blind the man or pierce the brain. He drove his coated fingers into the soft, liquid mucosal membrane just below the eyeball, delivering a concentrated, localized dose of the corrosive toxin directly into the villain's sensory nerves.

 

The reaction was instantaneous.

 

It was like dropping pure sodium into water. The acid reacted violently with the villain's fluid composition. A horrifying, agonizing screech tore from the Sludge Villain’s jagged mouth.

 

"MY EYE! BURNING! IT'S BURNING!"

 

The sheer, localized agony forced a massive, involuntary muscular contraction. The villain's body seized, losing its cohesive form. The sludge violently expelled the foreign object in its mass to divert energy to the pain.

 

Katsuki Bakugo was violently vomited out of the sludge, landing on the pavement, gasping and hacking up muck.

 

Izuku didn't hesitate. He grabbed Katsuki by the collar of his uniform, ignoring the blonde's coughing, and dragged him backward, away from the thrashing villain and the fire.

 

The Pro Heroes finally snapped out of their stupor. With the hostage free and the villain incapacitated by pain, Kamui Woods launched his Lacquered Chain Prison, wrapping the thrashing sludge mass in impenetrable wood before it could reform.

 

It was over.

 

The fires crackled, but the street was silent.

 

Izuku let go of Katsuki. He stood up, feeling a massive wave of dizziness wash over him. The acid generation had instantly consumed nearly two liters of water from his body. His mouth felt like cotton. His skin was flush with fever. He reached for his belt, pulling out a collapsible pouch of electrolyte water, and began to drink deeply, ignoring the stares of everyone around him.

 

Death Arms marched over, his face flushed with anger. He pointed a massive finger at Izuku. "You! What were you thinking?! Are you insane? You charged into a hostage situation with no backup! You could have gotten yourself killed, and you used an unauthorized, clearly dangerous Quirk! That was a lethal attack!"

 

Izuku capped his water pouch. He looked up at Death Arms. His green eyes were cold, analytical, and completely devoid of intimidation.

 

"It was not lethal," Izuku stated calmly, his voice projecting clearly through his mask. "I delivered a 0.5 milliliter dose of a Class-3 corrosive analog to the inferior conjunctival fornix. It caused instantaneous severe pain and minor localized tissue burning, triggering an involuntary expulsion reflex. The villain's eye will heal within three weeks with proper medical care. Furthermore, Pro Hero Death Arms, the victim had been suffering from acute hypoxia for over two minutes. If I had waited for an 'authorized' hero to arrive, Katsuki Bakugo would be dead."

 

Death Arms opened his mouth, but no words came out. The absolute, clinical certainty in the teenager's voice completely derailed his scolding.

 

"I assessed the risk," Izuku continued, his voice neutral. "I executed a non-lethal extraction. And the civilian is alive. Excuse me."

 

Izuku turned his back on the Pro Heroes, picked up his backpack, and walked away.

 

Katsuki Bakugo sat on the ground, still coughing up sludge, staring at Izuku's retreating back. The rage in Katsuki's eyes was gone, replaced by a deep, unsettling realization. Deku hadn't saved him with brute force. Deku had dissected the situation, found the exact mathematical solution, and executed it flawlessly.

 

 

 

High above the street, perched on the edge of a three-story rooftop, a man crouched in the shadows.

 

He wore a dark, ragged jumpsuit, a massive capture scarf wrapped around his neck, and yellow goggles resting on his forehead. Shota Aizawa, the underground Pro Hero Eraserhead, had been responding to the explosions, fully intending to intervene when the loud, flashy heroes below proved useless.

 

But he hadn't needed to.

 

Aizawa had watched the entire sequence of events. He had seen the green-haired kid calculate the villain's strike pattern, run the wall, and deliver a perfectly precise, surgically restrained attack that incapacitated the target without causing permanent damage.

 

Aizawa's eyes narrowed, a rare, genuine smirk tugging at the corner of his lips.

 

Logical, Aizawa thought. Completely and utterly logical. The heroes down there were paralyzed by variables. The kid stripped away the variables, found the single point of failure, and struck it. He didn't use an ounce more power than necessary.

 

He looked at the boy walking away, noting the heavy respirator mask and the insulated gloves. A dangerous Quirk, heavily controlled by a brilliant mind.

 

"Interesting," Aizawa muttered to himself, unwinding his scarf and preparing to swing away. "Let's see if you can survive the entrance exam, kid."

 

 

 

Ten Months Later. February.

 

The towering, H-shaped gates of U.A. High School loomed in the crisp morning air. The pinnacle of hero society.

 

Izuku stood at the back of the massive crowd of applicants, a sea of anxious teenagers vibrating with nervous energy. He was dressed not in his middle school uniform, but in a custom-tailored, tactical bodysuit he had commissioned from an online support gear company. It was deep forest green, woven with Nomex and Kevlar fibers to resist tears, but primarily designed with a porous micro-mesh inner layer that allowed his secreted toxins to pool and vent through localized exhaust ports on his shoulders, wrists, and calves. His heavy carbon-filter mask was securely locked over his lower face, his green eyes locked onto the massive doors of Battle Center B.

 

Inside the orientation auditorium, Present Mic had explained the rules. Three types of robots, worth one, two, and three points. A zero-pointer obstacle to be avoided.

 

Villains made of steel and wire, Izuku had noted. Biological warfare is moot. Toxins are useless. I must rely entirely on my corrosive output.

 

For the past three days, Izuku had consumed nothing but highly alkaline foods, citric acid concentrates, and massive volumes of water. His body was currently a pressurized vessel of a highly potent, custom-synthesized fluoroantimonic acid analog. It was the most dangerous substance his body could produce. It could dissolve glass, eat through steel plating, and violently react with internal circuitry.

 

"RIGHT, LET'S START!" Present Mic’s voice boomed from the watchtower. "GET MOVING! THERE ARE NO COUNTDOWNS IN REAL BATTLES! RUN, RUN, RUN!"

 

The massive gates swung open.

 

The crowd of applicants hesitated for a fraction of a second. That was all Izuku needed.

 

He didn't run. He engaged his Quirk.

 

He opened the exhaust ports on the soles of his boots. He triggered a rapid, exothermic reaction in his apocrine glands, instantly vaporizing a harmless, highly compressed nitrogen-analog gas.

 

Gas Propulsion: Active.

 

FWOOSH.

 

A blast of white, pressurized vapor erupted from Izuku's boots, launching him forward like a torpedo. He shot past the paralyzed crowd, flying low over the ground, passing through the gates before anyone else had even taken a step.

 

"Whoa! What was that?!" a girl with a round face and permanent blush (Uraraka, Izuku had mentally noted during orientation) gasped.

 

Izuku landed smoothly in a roll fifty meters inside the faux city, instantly springing to his feet. He was in his element. The urban environment provided verticality. He sprinted down the main avenue, his ears straining for the sound of servos and gears.

 

A massive, one-wheeled robot—a 1-Pointer—crashed out of an alleyway, its red optical sensor locking onto him. "TARGET ACQUIRED."

 

Izuku didn't slow down. He sprinted directly at the machine.

 

The robot raised a massive, blunt metal arm to swat him. Izuku dropped into a baseball slide, slipping perfectly under the swinging arm. As he slid beneath the machine's chassis, he reached up with his left hand, dialing his glove's valve to max output.

 

He didn't need to melt the whole robot. He just needed to destroy the brain.

 

He slammed his gloved palm against the robot's central underbelly panel. He released a half-second burst of his corrosive sweat. The acid instantly ate through the outer plating with a violent, hissing sizzle, biting directly into the main battery casing and the motherboard.

 

Izuku rolled out from under the robot and stood up, not even looking back.

 

Z-Z-Z-R-R-R-T.

 

The 1-Pointer spasmed wildly, sparks showering from its underbelly, before the acid caused a short circuit in the battery. The machine collapsed into a smoking heap of useless metal.

 

One point.

 

Izuku took off down a side street. He moved like a ghost, utilizing the shadows and the fire escapes to navigate. He didn't engage in flashy brawls. He was a surgeon in a warzone.

 

Three 2-Pointers rolled into the intersection ahead.

 

Izuku leaped off a dumpster, grabbing the railing of a fire escape and pulling himself up to the second floor. He looked down at the robots. He extended his right hand over the edge of the railing.

 

He adjusted the viscosity of his acid, turning it from a liquid into a sticky, gelatinous secretion. With a sharp flick of his wrist, he flung three globes of the acidic gel downward. They landed with wet smacks perfectly onto the optical sensors of the three robots.

 

The acid instantly melted through the glass lenses, blinding the machines and eating into their processing units. The robots began to fire their weapons blindly into the buildings, completely incapacitated.

 

Seven points.

 

For the next eight minutes, Izuku was a terror. He didn't roar, he didn't smash, and he didn't boast. He systematically disassembled twenty-five robots by targeting their joints, optical sensors, and power couplings with highly concentrated micro-doses of corrosive acid.

 

However, his body was paying the price.

 

By the nine-minute mark, Izuku was leaning heavily against a brick wall, his chest heaving. His core temperature was hovering around 103 degrees Fahrenheit. Sweat—normal sweat, not his Quirk—drenched his hair. His lips were cracked beneath his mask. He had consumed an entire liter of water from his tactical belt pouches, but the acid synthesis was draining him faster than he could replenish.

 

Current score: 54 points. Based on historical data, the cutoff is roughly 40. I have passed. Engage conservation mode.

 

He closed his eyes, forcing his heart rate to slow, shutting down his chemical refineries to prevent internal burning.

 

Suddenly, the ground beneath his feet violently pitched upward.

 

An apocalyptic grinding sound tore through the city. Izuku snapped his eyes open, looking down the main avenue. Buildings were shattering like glass. Rising from the dust cloud, eclipsing the artificial sun, was a monstrosity of green steel. It was easily the size of a skyscraper.

 

The Zero Pointer. The obstacle.

 

"LESS THAN TWO MINUTES REMAINING!" Present Mic announced.

 

Panic erupted. The other applicants, who had been fighting nearby, immediately turned and fled in terror.

 

"Run away!" a boy with engines in his legs yelled, sprinting past Izuku.

 

Izuku stepped out from the alleyway, watching the massive machine crush a four-story building beneath its treads. He had no intention of fighting it. It was illogical. It offered no points, and his acid reserves were too low to affect armor that thick. He turned to join the retreat.

 

"Ow! Help!"

 

The cry was faint, barely audible over the grinding gears of the behemoth.

 

Izuku stopped dead. His head snapped back toward the danger zone.

 

Through the settling dust, he saw her. The girl with the round face. She was trapped under a massive slab of concrete that had fallen from a destroyed building. Her ankle was pinned. She was struggling wildly, but she couldn't move it.

 

And the Zero Pointer’s massive, tank-like tread was rolling directly toward her. It would crush her in less than twenty seconds.

 

The other applicants were still running. Nobody looked back. Nobody noticed her.

 

Izuku didn't think. He didn't calculate his water reserves. He didn't assess the risk to his own internal organs.

 

The four-year-old boy in the sandbox, the boy who just wanted to save people, took the wheel.

 

Izuku broke into a dead sprint toward the Zero Pointer.

 

"Hey! What are you doing?!" a blonde boy with a sparkling belt yelled. "It's a zero pointer! You'll die!"

 

Izuku ignored him. He pushed his legs to their absolute limit, his gas-propulsion boots firing in short, rapid bursts to accelerate his sprint to superhuman speeds. The heat in his core spiked dangerously, a blinding headache slamming into his temples as his body cannibalized its remaining moisture to fuel the Quirk.

 

He reached Uraraka just as the shadow of the treads fell over them.

 

"Hold still!" Izuku shouted through his mask, dropping to his knees beside her.

 

He didn't try to lift the rubble. He wasn't All Might. He lacked the physical strength.

 

Instead, he slapped both of his hands onto the center of the concrete slab trapping her leg. He dialed his gloves to maximum output, fully opening the valves. He bypassed his safety limits.

 

Payload: Maximum Corrosive Dump.

 

A massive, hissing geyser of pure, highly concentrated acid erupted from his palms. The sheer volume of the chemical reaction produced a cloud of searing white steam. The acid ate through the dense concrete as if it were wet sugar. In less than three seconds, the structural integrity of the slab failed, crumbling into a pile of loose, melted gravel.

 

"My leg is free!" Uraraka cried, though she winced in pain, her ankle clearly sprained.

 

"Hold your breath and close your eyes!" Izuku ordered.

 

The Zero Pointer's tread was five feet away.

 

Izuku grabbed Uraraka around the waist, pulling her tightly against his chest. He aimed his boots directly at the ground. He had no water left. Using his Quirk now was going to burn him from the inside out.

 

He didn't care.

 

Maximum Gas Propulsion.

 

He forcibly vented every single ounce of pressurized gas stored in his lower extremities. The resulting blast was a deafening BOOM. The force of the expulsion shattered the pavement beneath them, launching Izuku and Uraraka backward, flying thirty feet through the air.

 

They cleared the blast radius just as the Zero Pointer’s treads crushed the spot where they had been resting.

 

Izuku twisted in mid-air, ensuring he took the brunt of the impact. He crashed into the asphalt, tumbling several times before skidding to a halt, his arms wrapped securely around the girl.

 

"TIME'S UP!" Present Mic's voice echoed, accompanied by a blaring siren.

 

The Zero Pointer instantly powered down, freezing in place.

 

Izuku lay on his back, staring up at the sky. His vision was swimming with black spots. His throat felt like it was lined with sandpaper. His muscles violently cramped, screaming for hydration. He reached trembling fingers to the release latch of his mask, popping it off.

 

He gasped for air, his chest heaving.

 

"Are... are you okay?" Uraraka asked, pushing herself up, her eyes wide with shock and gratitude. "You... you saved my life. You went back for me."

 

Izuku looked at her. Despite the blinding pain in his head and the severe dehydration wracking his body, he managed to curl his dry lips into a small, genuine smile.

 

"Heroes..." Izuku rasped, his voice barely a whisper. "...save people. It's... logical."

 

His eyes rolled back, and the world faded to black.

 

 

 

A week later, Izuku sat at his desk in his bedroom.

 

His mother had dragged him to the hospital after the exam, terrified by his severe dehydration and high fever. Recovery Girl had administered heavy IV fluids, chiding him for pushing his Quirk so recklessly, but ultimately giving him a clean bill of health.

 

On the desk in front of him sat a small, metallic disc. The U.A. acceptance letter.

 

He pressed the button. A holographic projection sprang to life. It wasn't All Might. It was the principal of U.A., Nezu, a small, immaculately dressed chimera.

 

"Greetings, Izuku Midoriya!" Nezu chirped, sipping from a teacup. "I am the principal of U.A. High School. I am here to deliver your results personally. You scored an impressive 54 points in the villain combat portion of the exam. A solid score, primarily utilizing a brilliant, tactical application of your Quirk to disable targets rather than destroy them."

 

Izuku leaned forward, his heart pounding against his ribs. 54 points. It was enough.

 

"However!" Nezu smiled, his black eyes gleaming. "The combat points are not the only metric we use. A hero must also save lives. U.A. is not merely a school for destruction; it is a school for rescue!"

 

The hologram shifted, displaying a video of Izuku sprinting back to save Uraraka, melting the rubble, and blasting them to safety.

 

"You risked your own physical well-being, pushing past your Quirk's hard limits, to save a fellow examinee," Nezu said softly. "For this, the judges have awarded you 60 Rescue Points! Bringing your total to 114 points! You passed with flying colors, Midoriya. In fact, you tied for first place!"

 

Izuku stared at the projection, his breath hitching. First place.

 

"Welcome, Izuku Midoriya," Nezu bowed. "This is your Hero Academia. Class 1-A awaits."

 

The projection fizzled out.

 

Izuku sat in silence. He looked at his black, calloused hands. They weren't weapons of mass destruction. They weren't the tools of a villain. They were the hands that had saved Katsuki Bakugo. They were the hands that had saved Ochaco Uraraka.

 

He stood up, walking over to his bookshelf. He pulled out a fresh, blank notebook.

 

He didn't write Hero Analysis for the Future.

 

He took a black marker and wrote, in bold, confident letters: The Antidote Hero: Panacea - Field Journal Vol. 1.

 

He had the power to poison the world. But he was choosing to be the cure.

 

The morning of the first day of high school is traditionally a time of anxious optimism. For Izuku Midoriya, it was an exercise in extreme biochemical regulation.

 

His alarm chimed at precisely 4:00 AM, a full three hours before he needed to leave his apartment. He did not hit snooze. He sat up, stripped off his compression sleepwear, and walked into his adjoining bathroom, stepping onto a digital medical scale.

 

Weight: 63.5 kg. Core Temperature: 37.2°C. Hydration Level: Optimal.

 

Izuku nodded to his reflection. The dark circles under his eyes were a permanent fixture, the physical toll of a brain that rarely stopped calculating and a body that never truly rested. Today was the day he would step into U.A. High School, the most prestigious hero academy on the planet. He could not afford a single mistake. He could not afford an accidental leak, a stray venting of gas, or a microscopic drop of corrosive sweat.

 

He moved to the kitchen. His breakfast had been prepared the night before: a perfectly balanced nutritional slurry designed to maintain a neutral blood pH. He drank it unenthusiastically, followed by a liter of electrolyte-infused water. He needed his internal reservoirs full. U.A. was an unknown variable. He had no idea what tests they would subject him to, so he needed his body primed to synthesize any chemical on demand—from paralytics to acids to heavy inert gases.

 

Returning to his bedroom, he carefully laid out his uniform. The standard U.A. uniform was a sharp gray blazer, white dress shirt, red tie, and dark green pants. But Izuku’s was slightly different.

 

After receiving his acceptance letter, he had submitted a highly detailed, legally mandated quirk-accommodation request to the school board. The uniform he wore had been tailored by U.A.’s support department. The inner lining of the blazer and shirt was woven with a breathable, carbon-mesh fabric that trapped and neutralized airborne toxins.

 

He dressed meticulously. Finally, he picked up his accessories. First, the gloves. They were sleek, black, and made of a non-reactive synthetic polymer, extending past his wrists and snapping securely under his shirt cuffs. Built into the palms and knuckles were microscopic, dial-controlled release valves.

 

Next was the mask. It wasn't the heavy, industrial respirator he wore during the entrance exam. U.A. had provided him with a state-of-the-art, low-profile filtration mask. It covered his nose and mouth, sleek and black, hugging his jawline perfectly. It looked less like a biohazard warning and more like high-end tactical gear, but its function remained the same. It filtered the air he breathed in to protect his internal chemistry, and more importantly, it scrubbed the air he breathed out, ensuring he didn't accidentally sedate his classmates with a sigh.

 

He clipped the mask into place. The familiar, comforting hiss of the seals locking engaged. He took a deep breath. Breathe in. Breathe out. Control.

 

"Izuku?"

 

He turned. His mother, Inko, stood in the doorway, her hands nervously wringing a dish towel. She looked at him, her eyes shining with unshed tears. She saw the mask, the gloves, the posture of a soldier preparing for a hostile deployment, and her heart broke just a little. But she also saw the gold buttons of U.A. High School gleaming on his chest.

 

"I'm ready, Mom," Izuku said, his voice slightly muted by the mask's vocal modulator, which gave his tone a smooth, synthesized clarity.

 

Inko walked over, hesitantly reaching out to adjust his red tie. She made sure not to brush his exposed neck, a conditioned reflex she hadn't been able to shake in ten years. "You look so handsome. You look like a real hero, Izuku. Just... promise me you'll be careful. Don't push yourself too hard. Drink your water."

 

"I have three liters in my bag, and the support department mapped out every water fountain on campus for me," Izuku reassured her, offering a warm smile that she couldn't see, though his eyes crinkled enough to convey it. "I'll be fine. I promise."

 

"Show them what you can do," Inko whispered, stepping back.

 

Izuku nodded, grabbed his yellow backpack, and walked out the door. The commute to U.A. was a blur of train rides and walking. The cherry blossoms were in full bloom, a picturesque spring morning, but Izuku’s mind was locked onto variables. How large was the classroom? What was the ventilation like? If he needed to vent a pressure build-up, where were the nearest exhaust ducts?

 

When he finally passed through the massive security gates of the school, the sheer scale of U.A. threatened to overwhelm him. The glass hallways were labyrinthine. He followed the signs for the Hero Course first-years, his boots clicking softly against the polished floors.

 

He finally found it. A door so massive it looked like it belonged on a bank vault, painted with massive red letters: 1-A.

 

Izuku stopped outside. He closed his eyes.

 

This is it. The elite. The best of the best. They aren't middle schoolers anymore. They're future pros. But will they see me any differently?

 

Before he could reach for the handle, he heard the muffled shouts from inside.

 

"Take your feet off of that desk! Don't you think it's disrespectful to our upperclassmen and the craftsmen who made it?!"

 

"Hah?! What middle school are you from, you extra? I'll put my feet wherever I want!"

 

Izuku sighed. The scent of caramel and ozone practically seeped under the doorframe. Kacchan. Of course he was in Class 1-A. Izuku reached out, gripped the oversized handle, and slid the massive door open.

 

The argument abruptly halted.

 

Izuku stepped into the room. Twenty pairs of eyes snapped toward him.

 

The boy standing by the desk was tall, with neat blue hair and glasses, his arm chopped through the air in a rigid, robotic motion. Katsuki Bakugo sat at the desk, his feet propped up, an arrogant sneer plastered across his face. But the moment Katsuki saw the green hair, the black gloves, and the tactical mask, the sneer vanished, replaced by a deep, instinctual scowl. Katsuki immediately pulled his feet off the desk and sat up straight, his red eyes narrowing.

 

The rest of the class stared. It was a bizarre sight. Most students customized their uniforms slightly, but Izuku looked like he was expecting a chemical attack.

 

The tall, blue-haired boy marched straight toward Izuku with purposeful, heavy strides. "Greetings! I am Tenya Iida, from Somei Private Academy!" Iida bowed at a perfect right angle.

 

Izuku instinctively took a half-step back, ensuring a three-foot radius between them. "I-Izuku Midoriya. Nice to meet you, Iida."

 

Iida straightened up, his eyes darting to the mask. "Midoriya, you placed first in the practical exam, tied with Bakugo! You realized there was a hidden metric, didn't you? The rescue points! I was completely blind to it. I misjudged you. I apologize!"

 

"Oh, no, I didn't figure it out," Izuku stammered, waving his gloved hands frantically, the clinical, cold demeanor he wore in combat melting away into pure, teenage social anxiety. "I just... saw someone who needed help, and my legs moved on their own!"

 

"That is the very essence of heroism!" Iida declared loudly, pushing his glasses up his nose. But then he frowned, gesturing vaguely at Izuku’s face. "However, if I may ask... is there a reason you are wearing a respiratory unit indoors? Are you ill? If so, you should visit the nurse—"

 

"Oh! That curly hair! The plain-looking boy!"

 

Izuku turned to see Ochaco Uraraka bounding through the doorway behind him, her face lighting up with a massive smile. "You passed! I knew you would! You were so amazing, melting that giant robot and flying us out of there! It was like a movie!"

 

Izuku’s face flushed violently beneath his mask. "I-it wasn't that amazing! I just... I mean, you saved yourself by keeping calm! I just applied an exothermic corrosive to the structural weak point..."

 

He started muttering, a habit he couldn't break, his voice dropping into a rapid-fire murmur. Uraraka blinked, leaning in closer, while Iida looked deeply confused.

 

"Deku."

 

Katsuki’s voice cut through the chatter. The blonde boy stood up, his palms smoking slightly. The rest of the class went quiet, sensing the history between the two.

 

"Don't think just because you pulled a flashy stunt with your villain trick that you belong here," Katsuki sneered, though he kept his distance. "You're a hazard. The moment you lose control, they'll expel you."

 

Uraraka frowned, turning to Katsuki. "Villain trick? Hazard? What's his problem?"

 

She turned back to Izuku. "Hey, Midoriya, what exactly is your Quirk? I saw you shoot acid, and then you made an explosion with your boots..."

 

Izuku froze. The dreaded question. For ten years, this was the exact moment when the dynamic shifted. The moment he explained what his body did, the smiles faded, the eyes widened, and the physical distance between him and whoever he was talking to increased. He looked at Uraraka’s bright, open face, and Iida’s respectful, attentive gaze. He didn't want them to look at him with fear.

 

But hiding it was a violation of protocol, and incredibly dangerous.

 

Izuku took a deep breath. His posture straightened, shifting from the nervous teenager back into the clinical analyst.

 

"My Quirk is called Toxic Synthesis," Izuku said, his modulated voice ringing clearly across the quiet classroom. He made sure to keep his hands folded behind his back. "My body functions as an advanced chemical refinery. I can alter my biology to secrete, exhale, and manipulate various chemical compounds. Acids, paralytic venoms, sleep gases, and neurotoxins. The mask and gloves are mandatory containment gear to ensure I do not accidentally poison anyone in this room."

 

Silence. Total, suffocating silence.

 

A boy with bright red, spiky hair in the back row gaped. A girl with earphone jacks hanging from her lobes pulled back slightly.

 

Iida’s eyes widened behind his glasses. He looked at Izuku’s gloves, realizing that the boy standing in front of him was, technically speaking, a walking biological weapon. "Toxins..." Iida murmured. "That is... an incredibly lethal power for a hero."

 

Uraraka looked at the mask, processing the information. The acid that melted the concrete wasn't just a generic energy blast. It was a chemical reaction. "So... you wear all that to protect us from you?"

 

Izuku looked down at his boots, bracing himself for the rejection. "Yes. I am registered as a Class-A Hazard. But I promise, my control is absolute. I monitor my output constantly. I will never let a civilian or an ally come into contact with my secretions. I want to be a hero who saves people without causing collateral damage."

 

He waited for them to back away. He waited for Iida to condemn his power as unfit for society.

 

Instead, Uraraka smiled. It was a little more subdued than before, but completely genuine. "Wow. That sounds... really exhausting, actually. Having to be so careful all the time. You must be super smart to keep track of all that chemistry stuff!"

 

Izuku’s head snapped up. "Y-you're not scared?"

 

Iida adjusted his glasses, his expression turning solemn and deeply respectful. "A Quirk is merely a tool, Midoriya. A knife can be used to harm, or it can be used by a surgeon to save a life. The fact that you bear the heavy burden of such a dangerous Quirk, yet go to such extreme lengths to ensure the safety of others... it is highly commendable! It shows immense discipline! A true hallmark of a U.A. student!"

 

Uraraka nodded enthusiastically. "Yeah! You saved me, didn't you? Nothing villainous about that!"

 

Izuku stared at them. A sudden, tight pressure built up in his throat, completely unrelated to his Quirk. For ten years, he had been called a freak, a hazard, a monster. And here, in the span of two minutes, these two strangers had accepted him. He felt a rare, overwhelming urge to cry, but he quickly fought it down, terrified of what his tears might biologically consist of.

 

"Thank you," Izuku whispered softly.

 

"If you're just here to make friends, you can pack up your stuff and leave."

 

The voice was gruff, exhausted, and seemed to emanate from the floor.

 

The entire class jumped, spinning toward the doorway. Lying on the floor, zipped inside a bright yellow sleeping bag like an oversized caterpillar, was a haggard-looking man. He had long, unkempt black hair, heavy bags under his eyes, and a juice pouch clamped between his teeth.

 

The man unzipped the sleeping bag and stood up, revealing a dark, ragged jumpsuit and a massive capture scarf around his neck. Izuku instantly recognized him. Eraserhead. The Underground Hero. He specializes in quirk nullification and non-lethal apprehension.

 

"It took you lot eight seconds to quiet down," the man sighed, scratching his neck. "Time is limited. You kids are not rational enough."

 

He walked to the podium. "I am Shota Aizawa. I'll be your homeroom teacher."

 

"Homeroom teacher?!" the class echoed in shock.

 

Aizawa ignored them, reaching into his sleeping bag and pulling out a blue and white track suit. "Put these on and head out to the P.E. grounds. We're doing a Quirk Apprehension Test."

 

 

 

The sun beat down on the massive outdoor athletic field of U.A. High.

 

Class 1-A stood in a cluster, wearing their P.E. uniforms. Izuku’s uniform, much like his school uniform, had been heavily modified. The sleeves extended down to connect with his specialized gloves, and the collar rose high enough to seamlessly lock with his tactical mask. The fabric was lined with thermal-regulation mesh to prevent him from overheating when synthesizing chemicals.

 

"A Quirk Apprehension Test?" Uraraka asked, looking nervous. "What about the entrance ceremony? The orientation?"

 

"If you're going to become a pro, you don't have time for leisurely events," Aizawa said bluntly, turning his back to them. "U.A. is a 'freestyle' school. That means I run my class however I see fit. You've been doing standardized fitness tests since elementary school. But you were never allowed to use your Quirks. That's irrational. The Ministry of Education is procrastinating."

 

Aizawa turned his gaze toward Katsuki. "Bakugo. You finished first in the practical exam. In middle school, what was your best result for the softball throw?"

 

"Sixty-seven meters," Katsuki replied, arms crossed.

 

"Try doing it with your Quirk," Aizawa said, tossing him a baseball. "Anything goes, just stay in the circle. Hurry up. Give it all you've got."

 

Katsuki smirked. He stepped into the painted circle, stretching his shoulders. Izuku watched closely, analyzing Katsuki’s posture. He's going to use a massive blast to propel the ball. The concussive force will shatter the sound barrier.

 

"DIE!" Katsuki roared.

 

He threw the ball, igniting a massive, blinding explosion from his palm at the exact moment of release. The shockwave ruffled the hair of the students standing twenty feet away. The ball shot into the sky like a rocket, leaving a trail of black smoke.

 

Aizawa held up a digital device. 705.2 meters.

 

"Know your own maximum first," Aizawa said lazily. "That is the most rational way to form the foundation of a hero."

 

The class erupted in excitement.

 

"Seven hundred meters?! That's insane!"

"We can use our Quirks as much as we want?! This looks like fun!"

 

Aizawa’s eyes narrowed. The exhausted, lazy demeanor vanished, replaced by a cold, predatory intensity that made the hair on the back of Izuku’s neck stand up.

 

"'It looks like fun,' you say?" Aizawa's voice dropped to a menacing growl. "You have three years to become heroes. Will you have an attitude like that the whole time? Alright then. New rule. Whoever comes in last place in all eight tests will be judged to have no potential... and will be punished with immediate expulsion."

 

A collective gasp echoed across the field.

 

"Expulsion?!" Uraraka cried out. "But it's the first day! That's not fair!"

 

"Natural disasters, massive accidents, and villain attacks," Aizawa listed off, his eyes sweeping over the terrified students. "Calamities can happen anytime, anywhere. Japan is covered in unfairness. Heroes are the ones who reverse those situations. If you wanted to go talk to your friends at Mickey D's after school, too bad. For the next three years, U.A. will throw terrible hardships at you. Go Plus Ultra. Overcome it with all you've got."

 

Izuku swallowed hard, his throat dry. Expulsion.

 

If he got expelled on the first day, his dream was dead. The doctor's words from ten years ago echoed in his mind. Adjust his career aspirations. He couldn't go back to being the useless, hazardous Deku. He had to prove he belonged here.

 

But there was a massive problem.

 

These are physical fitness tests, Izuku calculated frantically. My Quirk doesn't enhance my physical strength. I can't lift heavy things. I can't jump over buildings. My Quirk manipulates the chemical makeup of my surroundings. How do I apply biochemistry to a fifty-meter dash without accidentally poisoning a classmate?

 

"Test one: 50-Meter Dash," Aizawa announced.

 

Izuku lined up at the starting blocks alongside a boy with a tail (Ojiro, he recalled). A hovering camera robot acted as the judge.

 

Izuku closed his eyes. Think. I need speed. Gas propulsion worked during the exam, but that was an uncontrolled, explosive blast of compressed air. If I do that here, I'll melt my shoes and likely concuss Ojiro with the shockwave. I need sustained, controlled thrust.

 

He dialed the valves on his boots to a medium setting. He altered his internal chemistry, pulling nitrogen and oxygen from his bloodstream, compressing it rapidly in the lower apocrine glands of his calves. He didn't ignite it. He simply pressurized it.

 

"On your marks..." the robot chimed. "Get set..."

 

BANG!

 

Izuku snapped his boots open. A violent, hissing stream of highly compressed, harmless white vapor shot from the soles of his shoes. He didn't run; he essentially ice-skated on a cushion of pressurized air, his boots hovering an inch off the ground as the gas propelled him forward. He kept his body low, minimizing wind resistance.

 

He crossed the finish line in a blur of white mist.

 

"3.84 seconds," the robot announced.

 

Izuku skidded to a halt, cutting off the gas and panting softly beneath his mask. It wasn't the fastest—Iida had clocked in at 3.04 seconds—but it was fast enough to keep him out of the bottom ranks. He took a quick sip from his hydro-flask. Gas compression dried out his skin quickly.

 

"Test two: Grip Strength."

 

This was harder. Izuku stood by the grip-measuring device. He had no mechanical enhancements. His raw physical strength, while highly trained, was still human. He squeezed the device normally. 45 kg. Average.

 

He looked over. A massive, multi-armed boy named Shoji had just scored 540 kg.

 

I can't compete with mutation quirks in raw strength, Izuku thought, his mind racing. But... muscle tissue is just a biological engine. Engines can be overclocked.

 

Izuku looked at his right arm. He rolled up his sleeve. He reached into his own biology. He isolated his adrenal glands and specifically synthesized a massive, concentrated dose of epinephrine, mixed with a localized pain-inhibitor. He secreted the chemical cocktail directly into his own bloodstream, isolating it to his right arm to prevent cardiac arrest.

 

The veins in his right arm instantly bulged against his pale skin, turning a deep, angry shade of purple. The muscles visibly spasmed and swelled, supercharged with adrenaline.

 

Izuku gritted his teeth behind the mask, grabbing the device again. He squeezed. The pain was blinding—his muscles were tearing themselves apart from the unnatural tension—but the inhibitor kept him from dropping it.

 

The digital counter skyrocketed. 135 kg.

 

Izuku instantly released the grip, panting heavily, and rapidly synthesized a neutralizing agent to flush the adrenaline from his arm. His arm dropped to his side, trembling violently, feeling like it was packed with burning lead.

 

Aizawa, observing from the sidelines, raised an eyebrow. He noted the purple veins and the immediate flush of Izuku's skin. He's manipulating his own neurochemistry to force his body past its physical limits. Clever, but highly damaging. He's treating his own body as a test tube.

 

"Test three: Standing Long Jump."

 

Izuku stood at the edge of the sandbox. Gas propulsion upward was too risky; the aerodynamics were unstable, and he could break his neck on the landing. He looked down at the compacted sand.

 

Change the environment.

 

Izuku stepped up to the line. He channeled a highly specific, rapid-acting solvent into the soles of his boots. It wasn't a destructive acid; it was a compound designed to break down the silica bonds in the sand, turning the solid ground into a hyper-elastic, viscous gel for exactly three seconds.

 

He stomped his feet down, injecting the solvent into the earth. The ground beneath him bubbled and softened. Izuku squatted deeply, and as the gel rapidly expanded and snapped back to its solid state, it acted like a high-tension trampoline.

 

Izuku was launched into the air, soaring across the sandbox and landing cleanly on the other side.

 

Uraraka clapped from the sidelines. "Wow! He cleared the sandbox too! His Quirk is so versatile!"

 

Katsuki ground his teeth, watching Izuku succeed. He's not using his poison on us. He's using it on himself. He's playing it safe. Coward.

 

The tests continued. Repeated side-steps. Sit-ups. Seated toe-touch. Izuku relied on his rigorous, quirkless physical training to maintain an average score across the board. By the time they reached the final test, he was exhausted. His body temperature was dangerously high, and his mouth tasted like copper. He had burned through two liters of his water reserve.

 

"Test five: Softball Throw."

 

This was the decider. Uraraka stepped up and touched the ball, using her Zero Gravity quirk to send it into the stratosphere. Infinity.

 

Izuku stepped into the circle. He held the baseball in his gloved hand.

 

He looked at the digital scoreboard in his mind. He was hovering somewhere in the middle of the pack. The short boy with the purple balls on his head, Mineta, was likely in last place. But Izuku couldn't take chances. If he threw this ball normally, he'd get maybe fifty meters. It would tank his average.

 

He needed to launch it. Like Katsuki did.

 

Izuku stared at the ball. He could do it. He had studied the bombardier beetle for years. He could secrete hydroquinone from his right palm, and hydrogen peroxide from his left. If he coated the back of the ball with one, and struck it with the other, the resulting exothermic chemical reaction would create a concussive blast of boiling steam and pressure, easily launching the ball hundreds of meters.

 

But...

 

Izuku looked around the field. He saw Uraraka watching him eagerly. He saw Iida observing intently. He saw Katsuki glaring at him.

 

If I mix binary explosives... it's a volatile reaction. What if I miscalculate the dosage? What if the blast radius is too large? What if a stray droplet of boiling chemical hits Uraraka's eye? What if I blind someone? What if I prove them right? What if I am a hazard?

 

His hands began to tremble. His heart rate spiked, not from physical exertion, but from pure, unadulterated fear. The trauma of the sandbox, of Tsubasa's paralyzed body, screamed in his mind. Don't hurt anyone. Don't let it out.

 

Izuku squeezed his eyes shut. I'll just throw it normally. It's safe. Safe is better than sorry.

 

He drew his arm back, engaging his muscles, entirely abandoning his Quirk. He threw the ball as hard as his human arm could manage.

 

The ball sailed through the air and landed with a pathetic thud in the dirt.

 

The digital device beeped. 46 meters.

 

Izuku stared at the ground. He had failed. He had let his fear win.

 

"I erased your Quirk."

 

Izuku gasped, spinning around. Aizawa was standing ten feet away. His capture scarf was levitating wildly in the air around him, and his hair was floating. His eyes were glowing a piercing, unnatural red, locked directly onto Izuku.

 

"Eraserhead..." Izuku whispered.

 

Aizawa blinked, his hair falling flat as his eyes returned to their normal, exhausted black. "I watched you during the previous tests. You're intelligent. You manipulate your chemistry creatively. But just now... you hesitated. I saw the chemical buildup in your hands, and then I saw you cancel it. You were going to use an explosive reaction, but you pulled it back."

 

Aizawa took a step forward, his gaze cutting right through Izuku’s mask. "You're afraid of your own power."

 

Izuku flinched, instinctively taking a step back. "I... it's a binary explosive reaction. If the wind shifted, or if the dosage was off by a milliliter, the boiling vapor could have caused severe burns to the students behind me. I couldn't take that risk. I'm a Class-A Hazard."

 

"You're a student at U.A. High School," Aizawa corrected sharply, his voice carrying across the silent field. The rest of the class watched in stunned silence. "Do you think villains care about the wind shifting? Do you think a hostage situation pauses so you can double-check your math?"

 

Aizawa walked up to the edge of the circle. He didn't look angry; he looked disappointed, which somehow hurt worse.

 

"You've been told your whole life that your power is dangerous," Aizawa said, his voice dropping so only Izuku could hear the specific nuance, though the class heard the words. "You've been conditioned to believe that you are a villain waiting to happen. So you hold back. You self-sabotage. You cripple yourself because you think if you go all out, you'll become a monster."

 

Izuku's hands clenched into fists at his sides. Tears pricked his eyes, stinging against the seal of his mask. "If I lose control, people die."

 

"Then don't lose control," Aizawa stated simply, as if it were the easiest thing in the world. "A Quirk doesn't make a villain, Midoriya. Hesitation does. If you hesitate in the field because you're scared of your own shadow, a civilian dies. Your poison is a weapon. It is a lethal, terrifying weapon. So is a gun. So is Bakugo's explosion. So is Todoroki's fire."

 

Aizawa pointed to the bucket of baseballs. "If you refuse to pull the trigger because you're scared of the noise, you don't belong in my class. You cannot be a hero if you do not trust yourself. I don't want to see the boy who cowers behind a mask. I want to see the hero who masters his poison. Do it again."

 

Izuku stood frozen.

 

The words echoed in his mind, shattering a decade of internalized trauma. A Quirk doesn't make a villain. Hesitation does.

 

For ten years, doctors, teachers, and neighbors had told him to suppress it. To hide it. To be ashamed of it. Aizawa was the first adult in his entire life to look at his lethal, terrifying power and say: Use it.

 

Izuku walked over to the bucket. He picked up another baseball. He stepped back into the circle.

 

He didn't look back at the class. He didn't look at Katsuki. He focused entirely on the leather seams of the ball.

 

He took a deep, shuddering breath, the filters in his mask hissing loudly. He closed his eyes and visualized his internal chemistry. He stopped fighting the heat in his core. He let the engine roar to life.

 

He channeled hydroquinone into the sweat glands of his right palm. He channeled hydrogen peroxide and a specialized organic catalyst into the glands of his left hand.

 

Calculated dosage: 15 milliliters per hand. Ignition delay: 0.1 seconds. Vent angle: 45 degrees upward to clear the civilian radius.

 

Izuku opened his eyes. They weren't the fearful, wide eyes of a traumatized child anymore. They were sharp, focused, and burning with analytical intensity.

 

He drew his right arm back, clutching the ball. He brought his left hand up, hovering just an inch behind his right wrist.

 

"Go," Izuku whispered.

 

He threw the ball. The moment the ball left his fingertips, he snapped his left palm against the back of his right hand.

 

BOOM!

 

The binary chemicals mixed in the open air directly behind the ball. The reaction was instantaneous and violent. A massive, concussive explosion of boiling, pale-yellow steam erupted from his hands. The sheer kinetic force of the chemical blast hit the baseball like a sledgehammer, breaking the sound barrier with a deafening CRACK.

 

The wind pressure from the explosion whipped back, tearing across the field, but Izuku had angled it perfectly. The steam dissipated instantly in the upper atmosphere, completely harmless.

 

The ball vanished into the clouds, leaving a streak of vapor in its wake.

 

Izuku stood in the circle, his right arm smoking faintly, the leather of his glove slightly charred but intact. He didn't drop his arm. He slowly turned his head to look at Aizawa, his green eyes blazing with newly ignited confidence.

 

Aizawa didn't smile, but a glint of genuine approval flashed in his dark eyes. He held up the digital device for the class to see.

 

705.3 meters.

 

One tenth of a meter further than Katsuki Bakugo.

 

"He... he got over 700 meters?!" Denki Kaminari yelled, his jaw dropping.

 

"Without a strength quirk!" Uraraka cheered, pumping her fists. "I knew he could do it! He just used science!"

 

"Incredible application of hypergolic propellants!" Iida praised, furiously taking notes.

 

"DEKU!"

 

The roar was animalistic.

 

Izuku turned just in time to see Katsuki charging at him, his face twisted in a mask of absolute, unhinged fury. Explosions crackled violently in both of his palms. He wasn't just angry; he was threatened. The weak, useless Deku had just beaten him at his own game, using an explosion.

 

"Tell me how you did that, you villainous freak!" Katsuki screamed, leaping into the air, preparing to blast Izuku point-blank.

 

Izuku didn't flinch. He calmly raised his left hand, his thumb resting on the release dial of his glove, ready to deploy a heavy paralytic gas to shut Bakugo down.

 

Before either of them could act, thick, gray cloth wrapped around Katsuki’s torso like a python.

 

Katsuki was yanked out of the air, crashing hard into the dirt. His explosions instantly fizzled out. He struggled against the bindings, but they were unyielding.

 

Aizawa stood ten feet away, his capture weapon extended, his eyes glowing red once more. "What are these... hard... cloths?!" Katsuki grunted, thrashing on the ground.

 

"They are weapons for capture made of carbon fibers woven with metal wire made of a special alloy," Aizawa said coldly, reeling Katsuki in slightly. "Stop using your Quirk so much, Bakugo. I'm getting dry eye."

 

Aizawa blinked, releasing the cloth. Katsuki scrambled to his feet, panting heavily, glaring daggers at Izuku, but he didn't attack again. He knew better than to cross Eraserhead.

 

"We're wasting time," Aizawa sighed, turning away and pulling out his eye drops. "Whoever's next, step up."

 

 

 

The rest of the tests passed in a blur of exhaustion. When it was all over, the class gathered around a large holographic scoreboard projected from Aizawa’s device.

 

Izuku scanned the names. He didn't care about being first; he just needed to survive.

 

1. Momo Yaoyorozu

2. Shoto Todoroki

3. Katsuki Bakugo

4. Tenya Iida

...

9. Izuku Midoriya

 

He was in the top ten. He let out a long, shuddering breath, his shoulders slumping. The tension that had been coiling in his chest since 4:00 AM finally snapped. He was safe.

 

"By the way, I was lying about the expulsion," Aizawa said flatly, turning off the projector.

 

The class froze.

 

"It was a rational deception to draw out the upper limits of your Quirks," Aizawa continued, a massive, terrifying grin spreading across his face.

 

"WHAT?!" the majority of the class shrieked.

 

"Of course it was a lie," a tall girl with a ponytail—Yaoyorozu—sighed, shaking her head. "It should have been obvious if you just thought it through."

 

Izuku didn't care if it was a lie or not. It had worked. It had forced him to cross a mental barrier he had been trapped behind for a decade.

 

"With that, we're done here," Aizawa said, turning to walk away. "There are handouts with the syllabus and such in the classroom. When you get back, look them over."

 

As the class began to chatter excitedly, moving toward the locker rooms, Aizawa stopped. He glanced over his shoulder.

 

"Midoriya. A word."

 

Izuku stopped, signaling for Uraraka and Iida to go on ahead. He walked over to Aizawa, standing at rigid attention.

 

Aizawa looked the boy up and down. He noted the charred glove, the heavy breathing, and the slight tremor in Izuku's legs from dehydration.

 

"You passed the test, Midoriya," Aizawa said quietly, ensuring the other students were out of earshot. "Your tactical analysis is exceptional. Your control over your biology is impressive. I have read your Quirk registry file. I know the legal restrictions placed on you by the government."

 

Izuku stiffened. "Sir, I have all the proper permits for the mask and the—"

 

"I don't care about the permits," Aizawa interrupted. "I am your teacher now. The government labels you a hazard because they are cowards who fear what they can't punch. I don't deal in fear. I deal in logic."

 

Aizawa stepped closer. "You are allowed to wear your containment gear. But listen to me carefully. I will not tolerate you holding back in combat training. You are going to learn how to wield your toxins not as a liability to be contained, but as a scalpel to dissect your enemies. If I catch you putting yourself or your classmates at risk because you hesitated to use a paralytic, I will expel you for real. Understood?"

 

Izuku looked up into Aizawa’s tired, dark eyes. He didn't see a doctor looking at him with pity. He didn't see a mother looking at him with fear. He saw a mentor who demanded excellence, fully accepting the lethality of his power.

 

Izuku bowed deeply, a massive weight lifting off his shoulders.

 

"Yes, Sensei. Thank you."

 

 

 

The sun was setting, casting a warm, golden hue over the streets of Musutafu.

 

Izuku walked out of the U.A. gates, his muscles aching, his throat parched, but his spirit soaring higher than it ever had in his life. He was officially a U.A. student. He was going to be a hero.

 

"Hey! Midoriya!"

 

Izuku turned. Jogging down the path toward him were Uraraka and Iida.

 

"Are you taking the train to the station?" Iida asked, adjusting his backpack. "We can walk together, if you are agreeable to it!"

 

"Yeah!" Uraraka smiled, falling into step beside him. "You were so cool today, Midoriya! That explosion trick with your chemicals? Totally bad-ass! Bakugo looked like he was going to pop a blood vessel!"

 

Izuku chuckled, the sound slightly metallic through his mask. "It was just a basic hydroquinone reaction. But... thank you. Really."

 

He looked at the two of them walking beside him. They weren't keeping a three-foot distance. Uraraka bumped her shoulder against his arm as she laughed at a joke Iida made about school regulations.

 

They didn't see a biohazard. They just saw Izuku.

 

He took a deep breath, the carbon filters in his mask hissing softly. The air smelled like cherry blossoms and ozone, but inside his mask, it was just clean, sterile air.

 

He wasn't a monster. He was Panacea. And his training had only just begun.