3- Apartment
The key was in his left pocket.
He hadn't put it there. The original had, probably this morning, before a class he'd never finish sitting through. Ryo fished it out on the landing of the third floor, a small brass key on a ring with nothing else on it. No keychain. Just the one key.
The door was the second on the left. 302. He knew that with the flat certainty of someone else's muscle memory. His hand went to the lock without thinking, turned without looking. The body knew the door. Ryo had never seen it before.
The apartment was small. One room with a kitchen counter along the back wall, a door to what was probably a bathroom, a window with the blinds half up. The floor was clean. The air was stale, windows that never opened and nobody cooking anything with a smell.
A bed. Single. Sheets that were gray, not because they'd been bought gray but because they'd been washed enough times that whatever color they'd started as had given up. A desk pushed against the wall under the window, empty except for a pen and a few blank papers. A closet with a sliding door, cracked open enough that he could see dark fabric inside.
He slid the closet open. Black hoodies, black shirts, dark jeans, two identical U.A. uniforms on hangers. A pair of running shoes at the bottom with the tread worn down on the left heel more than the right. The original walked with a slight lean. Ryo hadn't noticed it in the body yet but the shoes didn't lie. On the top shelf, a shoebox with no shoes in it. He pulled it down. Inside: a phone charger, some receipts from convenience stores, a pen that had run out of ink, and a photo. Polaroid. The original with a girl who had short dark hair, both of them in school uniforms, standing in front of a vending machine. Neither of them was looking at the camera. They were looking at each other. The girl was laughing.
He checked the bathroom. Tile floor, narrow shower, one towel on the rack. A toothbrush in a cup by the sink, bristles bent sideways from use. The mirror over the sink was the first mirror he'd looked into since arriving, and for a second he just stood there. Messy black hair, sharp eyes, angular jaw. A face he recognized from memory but had never seen from this side. Younger than he'd expected. The face matched the memories but not the person behind the eyes, and that was still strange.
The ceiling had a stain. Brown, vaguely the shape of a bird with one wing spread and the other folded, like it was mid-turn. Water damage from the apartment above, probably. The stain had been there long enough that the edges had gone soft, bleeding into the off-white around it. Ryo stood in the middle of the room and looked up at it.
This was where the body went home to. Every night for however many years. No parents, no siblings, nobody waiting. The orphan stipend covered rent and food and not much else. There was a rice cooker on the counter and two bowls in the drying rack and a fridge that, when he opened it, contained half a carton of milk, some leftover rice in a container, and three eggs. The fridge hummed. Loud enough to hear from the bed, probably.
He sat down on the bed. The mattress dipped under him, and the body settled into the shape like it had done this ten thousand times. His hands rested on his knees. His heart rate was normal. The apartment was quiet.
Ten hours in this world and he hadn't had a minute to think. Properly think. Everything since the classroom had been reaction, performance, holding back. Now there was nothing to react to. Just the apartment and the body and the questions it came with.
The biggest one: why was he this strong?
He needed to go through the memories. Properly. The full archive, year by year, instead of the panicked scan he'd done in the classroom.
He kicked off his shoes and lay back on the bed. The pillow smelled like cheap detergent and nothing else. The bird stain was up there on the ceiling.
The Quirk was registered as "Enhance." Physical augmentation. The doctors had flagged it at age four or five, the standard age for Quirk manifestation. Kid gets stronger, runs faster, takes hits better than he should. Straightforward. The registration paperwork listed it as an Emitter-type, but that was probably wrong. Accumulation was closer. The strength built up over time, and once it built, it stayed.
But the rate of building didn't make sense.
Ryo went through it year by year, pulling from memory like scrolling through a phone gallery belonging to someone else. Childhood was normal. Quirk manifested, kid got a little stronger every year, nothing dramatic. The growth curve was gentle, steady, unremarkable. Doctors said he was a slow developer. Fine. Lots of kids were.
Then middle school. First girlfriend.
Her name was Aoi. He could see her face in memory, round, short hair, liked to laugh too loud. They'd dated for four months. The first kiss had been behind the school gym during a culture festival, standing next to a vending machine, and the memory of it was warm and clumsy and not his.
After that kiss, the growth curve changed.
The changes were gradual. But in the weeks following, the original Ryo had put on visible muscle without changing his routine. His sprint times improved. His grip strength jumped. The school nurse noted it at the next physical and said "growth spurt" and that was that.
Aoi and the original broke up three months later. Amicable. She liked someone else. The growth plateaued.
Second girlfriend. Hana. Taller than Aoi, quieter, they'd dated for most of the second year. The memories of Hana were warmer and more physical. They'd kissed more. Done more than kissing. Not sex, but hands under shirts, her breath on his neck in a park after dark, stuff that felt enormous when you were fourteen and barely registered when you were older. Going through someone else's physical memories was like hearing music through a wall.
During Hana, the growth curve climbed. Faster than with Aoi. The gains were bigger, coming in waves that lined up, when he mapped them against the relationship timeline, with physical milestones. First makeout session: jump. First time her hand went under his shirt: jump. First time his went under hers: bigger jump. The original hadn't connected any of this. He'd thought he was finally hitting puberty properly.
Hana and the original split at the end of second year. Growth stopped.
Between the breakup and the U.A. entrance exam, four months of nothing. Flat line. He maintained what he had, didn't gain, didn't lose. The original had chalked it up to the stress of exam prep. Ryo, lying on the original's bed and staring at the original's ceiling stain, could see the pattern so clearly it was almost insulting that nobody had caught it.
First kiss: first jump. First girlfriend: steady climb. Physical escalation: steeper climb. Breakup: plateau. New girlfriend: climbing again. More physical activity: faster climbing. Second breakup: plateau.
The Quirk wasn't physical augmentation triggered by willpower or training or combat stress or any of the normal triggers that enhancement Quirks ran on.
It was triggered by sexual activity.
Any sexual activity. With another person. Kissing counted. Touching counted. More counted more. The gains were permanent once earned, and they scaled with intensity. His current strength, the strength that had punched through entrance exam robots and placed fourteenth in the Apprehension Test while holding back, came from two teenage relationships and whatever the original and his girlfriends had done in parks and behind school gyms.
Ryo stared at the ceiling bird.
He tried to find another explanation. Training, maybe. The original had been active, walked to school, did gym class. But the gains didn't track with exercise. They tracked with girls. Every single time. The pattern was clean enough to graph. He could see the graph in his head, his whole history of growth plotted against his romantic history, and the two lines moved together like they were the same line.
Sex. His Quirk ran on sex.
His Quirk was sex-powered. He was enrolled in a hero school full of attractive teenagers with superpowers. In a few months, they'd all be living in co-ed dorms. His foreknowledge told him he was going to need to be a lot stronger than mid-pack if he wanted to survive USJ, the Forest Camp, and everything after. And his only path to getting stronger was to get laid.
He wasn't sure if that was hilarious or horrifying. Possibly both.
Because here was the problem. If he used it, if he pursued relationships and got stronger, every girl he was with became a lie. They'd think he liked them for them. And he would. But he'd also be getting stronger every time they kissed him, every time they did more, and they wouldn't know that. Nobody could know that. The registered Quirk said "Enhance." The cover story was physical augmentation. If anyone figured out the real trigger, every relationship retroactively became was he using me for power?
He sat up. The room was getting dark. He hadn't turned on a light.
He reached over to the desk and picked up the pen. Felt the weight of it in his fingers. He could write this down. A timeline of gains, a map of the pattern, notes on what the Quirk needed and what it gave. It would help to have it on paper. He was going to need to plan.
He put the pen back.
Everything stayed in his head. The pen and the blank papers on this desk were the most dangerous objects in the apartment. Nezu ran this school. Aizawa lived in the building. If anyone found a document linking sexual activity to Quirk development in a student's apartment, the questions that followed would end him.
Ryo got up and walked to the kitchen. Opened the fridge. Looked at the three eggs and the half-carton of milk and the rice. Closed the fridge. He wasn't hungry. Or he was, but the hunger felt secondhand, like the memories.
Midnight was somewhere in this city right now. Alive. Grading papers, probably, or drinking with Aizawa and Present Mic at whatever bar heroes went to after hours. She didn't know her name was on a list in his head.
He went back to the bed. Turned off the light. The bird stain on the ceiling was invisible in the dark but he knew where it was.
Outside, a siren went off somewhere and faded into the distance, and that was a sound that meant a rescue or a disaster or both in this world, where the sirens might be chasing someone who could level a city block with their hands.
Tomorrow was the second day of school. He hadn't done the homework. He wasn't sure if there was homework. His memories didn't cover today because today was the first day the body and Ryo had been the same person.
He closed his eyes. The mattress held the shape of someone who wasn't him.