Izuku recited to himself over and over again: Thirty-one days. Thirty-one days. Thirty-one days. His lips barely moved. Only a sigh of a sound escaped. It was a miniscule gesture of resistance. No matter how long he remained like this, lying on a king-sized bed unable to move and staring at steel walls, he refused to lose track of time. If he lost track of time, then he'd be truly lost.
The vault door ground open. All for One entered the room. Izuku referred to his father as All for One inside his head, never Hisashi Midoriya. The man who had hurt so many people and kidnapped him was not his father. Would never be his father again. Any good memories from his childhood, his father chasing him pretending to be a villain and analyzing quirks together, had been locked tightly in a memory box and sealed away.
As All for One approached, Izuku gnashed his teeth in the air. That was all he could do. Thirty-one days ago, All for One had used a quirk to paralyze Izuku from the neck down.
All for One chuckled in response. "Feeling grumpy?" he murmured, smoothing back his son's hair as if handling a small, fussy child.
When All for One changed his diaper, Izuku closed his eyes and tried not to think about it. Since he had no sensation in his body, he could pretend nothing was happening if he didn't see. Tiny tears of humiliation stung his eyes.
Afterward, All for One spoon-fed ramen to Izuku. Although Izuku had briefly tried a hunger strike, All for One could use his quirk to puppeteer Izuku's body as well as paralyze it, so that had done him no good. The villain could simply force Izuku to chew and swallow. The sensation had been so creepy, it was better to eat of his own free will. These days, meals were one of his only sources of entertainment. The food was good quality. All for One probably brought it from the best restaurants in Japan not decayed away.
Izuku had tried to plan an escape, but when completely unable to move his body, there was simply nothing he could do. He'd fantasized about sinking his teeth into All for One's throat and forcing the villain to remove the paralyzation. But in reality, All for One would never give him the opportunity and could simply puppeteer his body off anyway. Izuku's best hope was rescue. But in a month, no one had come for him. Izuku had his doubts there were any heroes left to save him. Because he'd failed the world.
It had all started with chronic pains running through Izuku's arms. Soon he'd been unable to lift heavy objects. Shortly afterward, he'd ceased to be able to walk. Then his arms had refused to raise over his head. The pain had gotten worse and worse. Even when lying still in bed, Izuku had been in agony. Trying to summon just the tiniest bit of One for All's power caused his bones to shatter before he even moved enough to punch something. When All for One had come for him and abducted him from the hospital, he'd been completely helpless.
Without One for All, the strongest unstealable quirk, the war against All for One had gone poorly. All for One had successfully stolen both Erasure and Rewind, resurfacing with a healed face and conquering entire cities in mere days. Before his abduction, Izuku had been desperately and unsuccessfully seeking medical treatment so he could fight again. People had not been willing to tell him how the war was going for fear of upsetting him, so all his information was out of date. His father told him even less. He had no idea what was going on outside now. But he knew it wasn't good.
Izuku Midoriya, the Ninth holder of One for All, had been the one to lose the battle to All for One. Self-hatred burned deep inside of him.
Most days, Izuku could do little except replay all his mistakes. He wished he'd listened to Recovery Girl's warnings. Her kisses had long ago stopped working on him. He wished he'd carefully rationed out every single use of One for All. Why had he wasted so many broken bones on pointless training exercises and the Sports Festival? If he'd known this would happen, he would have made sure every single one of his punches landed on a villain.
If he'd known this would happen, he never would have accepted One for All. Not for his own sake, but for the world. He hadn't been good enough.
Against Izuku's will, a small whimper escaped his mouth. His father held him to his chest, soothing him and petting his head. It would have been a great opportunity to bite, but his teeth weren't at the right angle.
"Leave me alone," Izuku growled. All this babying just made him feel even more pathetic.
"You need a bath first." All for One was merciless in his care. He refused to let Izuku develop bed sores in peace. Or to just let him die.
Once again, Izuku had no choice but to lie still as his father carried him out of the vault, into a bathroom with a large, steaming hot tub. Once again, he closed his eyes and pretended nothing was happening. That was what he'd been reduced to. Every time his arm was lifted and soap rubbed under, he felt like a puppet moving around at All for One's will. That had been all he'd turned out to be, in the end. A useless Deku. It had been cruel that he'd dreamed of more for a brief year at hero school, only to find out that his life could get even worse than he'd ever imagined.
As his father carried him back into the vault, Izuku snarked, "What's the point of this? I can't escape. You'd like me to believe there's no one left to rescue me. Then why lock me up behind thick steel walls? Do you just love bank vaults so much you seize on any excuse to use one? You've got issues."
All for One laughed. "I just happened to have a room already prepared in here, that's all." He tweaked Izuku's nose. "And it does warm my heart to see you safe with my other treasures." He gestured at the demon king merchandise around the room.
Izuku had tried spitting on it a few times, but he couldn't spit that far, and his father had only laughed. Apparently, All for One enjoyed it when Izuku defied him and fought with him, as long as Izuku couldn't do so with any real success. It was like a child playing with a kitten, dangling a ball of yarn over the tiny claws. Since realizing this, Izuku had tried to stop the pointless insults that only entertained his captor. He'd had mixed success. He got so bored, it was hard to keep his mouth shut. And suffering had turned him mean.
Next, All for One lifted Izuku's arms and legs in a series of exercises. They were necessary to prevent him from getting sores. But Izuku hated the touches he could not throw off. Once, Izuku's body had been covered in muscles he'd worked hard to develop. He'd been proud of the results of his training. Now his arms and legs had become desiccated sticks. It pained him to even look at his body.
All for One pressed a kiss to Izuku's forehead. "I love you, ducky." Then the villain finally left.
Izuku did not know if it was a relief or a torment to be alone again. He hated All for One's presence, but he also hated the lonely vault with the stupid silk sheets and ever-present hum of the ventilator.
All for One had not been quite cruel enough to leave Izuku with no entertainment. The far wall had a large screen TV. The television was voice activated, allowing Izuku to pick what he wanted to watch. A wide range of shows and movies from the dawn of the age of the quirks to the present had been loaded, but no hero shows. He was not allowed to watch the news. (Assuming any media still survived outside.)
Despite these options, Izuku lay in silence, trying to think up a plan.
He'd once been proud of his strategic ability, but now he had no resources and he couldn't think straight. No matter how hard he tried, nothing came. Whenever Izuku was left alone like this, the muscle spasms started. Whatever his father had done to him, he could not feel his body move, but he watched his legs jerk under the sheets. His entire lower half would thrash like a fish out of water, squeezing his lungs as he lay helpless on his back. Sometimes he heard it when he urinated, and smelled the stench. Scent packets around his bed mostly clogged his nose with peppermint and let him keep his denial.
The itches always came soon after. Izuku had always been able to endure pain. In the past, he'd fought with several broken bones. But he hadn't known hell until he'd experienced an itch on his nose with no way to scratch. All his fragile attempts to plan slipped away with the burning need to itch itch ITCH.
So many times, Izuku had tried to reach up to scratch his nose, only to find out his hands wouldn't move. He kept forgetting. Every reminder was cruel.
Izuku could voice-activate a button to call his father. He didn't like to stoop so low as to use it. Not over mere itches. Also, his father always demanded rewards for such special favors as itching his nose for him, like kisses or saying that he loved his dad. Izuku would rot in his own filth first.
Yet perhaps the worst part of all? Even Izuku's current suffering was better than before his paralyzation. His constant pain from overusing his quirk had been agonizing. It had felt like every single nerve in his body was on fire. He'd been unable to sleep except when drugged to the gills. He'd had only a little more mobility than right now, at the cost of horrific pain each time he lifted his finger. Some days he was even a little grateful to the villain who'd paralyzed him. Most days he just wished he could stop his breathing and end all of this.
Oh, how the helplessness burned. For a brief moment in the sun, Izuku had been a hero. Now he couldn't even use the bathroom.
Why had All for One done this to him? A twisted punishment disguised as fatherly love? A way to hurt the last holder of One for All without killing the son he treated as his property?
Izuku decided to give his father the silent treatment. This was the closest he could come to a plan. Maybe this would force All for One to negotiate. Or at least he'd spite his captor. If All for One wanted to own his son, then he'd receive nothing except a useless puppet.
On day thirty-two, Izuku maintained a perfect silence. His father barely seemed to notice. By day thirty-three, All for One started trying to jolly him out of it. This time, All for One stayed long enough to watch a movie with Izuku and make frequent annoying commentary. By day thirty-four, All for One offered tantalizing hints about what might have happened to Izuku's friends outside. Izuku resisted even such delicious bait. His dad was finally unhappy. That meant Izuku was winning.
On day thirty-seven, All for One brought in a jar of white pills. Antidepressants, he called them. Izuku didn't trust anything his father's twisted doctor had made. But with his body moving against his will, he had no choice but to swallow them down.
Izuku felt no immediate effects. But he was worried, very worried. All for One had made his point. He could force Izuku to do whatever he wanted. If Izuku still didn't speak, he'd probably be put on more intensely mind-altering drugs. Izuku did not doubt for one second that All for One could find something to make Izuku babble like the baby he got treated as. Then any meager hope of escape would be gone.
Fear gripped Izuku. He'd lost control of his body. He had nothing left but his mind. If he lost that too, he'd truly be better off dead.
Izuku needed a new plan. The spiteful resistance hadn't gotten him anywhere. It would never get him anywhere, no matter how badly he wanted to believe otherwise. There was only one option left. Izuku didn't like it, but he ought to have tried it back on day one. He had to fake compliance to get his father to remove the paralyzation quirk.
So Izuku completely changed tactics.
When All for One entered on the thirty-eighth day, Izuku said, "I don't like being drugged. I'll cooperate if you don't give me any more pills."
All for One kissed his forehead. "I don't like drugging you either, ducky. I don't ask much of you. Just try to exercise your mind and talk to me a few times a day. This is for your own good."
Izuku knew it would be suspicious if he changed too quickly. His father might be a bastard, but not a fool. So he used his desire to get off the drugs as an excuse to start conversations. At first, Izuku snarked and disagreed with his father about everything from movies to the food. Slowly, Izuku started using his button to call for help when he had an itch or needed a diaper change. The first time his dad asked for a kiss, he wrinkled his nose but complied. Gradually, he stopped showing revulsion toward affection. The cheek kisses never stopped being unpleasant to Izuku. But his father preferred believing he got them willingly.
When receiving compliance and love, All for One became even more doting. He carried Izuku around, even taking him to a greenhouse to get sunlight a few times. Izuku felt like a stupid baby being carted around. But he endured. He counted the days. He needed to last at least a few weeks to be convincing, he reckoned. A month would be smartest.
Every single night, All for One told Izuku, "I love you, ducky."
On the sixtieth day, Izuku said, "I love you too, Dad."
All for One's eyes widened. He scooped up his son into his arms and peppered his face with kisses. "I'm glad you're doing so much better," he murmured. "We'll remove that nasty hero brainwashing yet."
Izuku had planned to wait another week to launch the next stage of his plan, but he could endure no more. He begged, "Please, Dad, won't you remove the paralyzation? I'll be good. I won't try to fight you any longer. I don't have any desire to escape anymore. I promise."
All for One looked down with a sad frown. "Oh, ducky. I told you a million times, I only paralyzed you to take away your pain. I'm your father. I would never hurt you. If I had any other choice, I wouldn't leave you in suffering. This was the only way I could save you from that dreadful cursed quirk."
"But you could heal me! You could take away my pain! You have Rewind, you used it to heal your own body. You could cure my body, too." Izuku babbled, begging, "Please, I can't live like this, it's too painful. If you heal me, then I'll play games with you and give you all the hugs you want. I'll do anything to make you trust me. Anything you ask. I'll give you One for All."
Izuku stopped talking. He wanted to believe the words that had left his mouth were a lie. Except in that moment, he knew he'd do it. It was a betrayal to All Might and the legacy of One for All and his heroic dreams and everyone he loved. But even so, Izuku would give up One for All without hesitation just to move his arm without pain again.
All for One brushed Izuku's hair. "Don't you remember, ducky? I already tried to heal you with Rewind. I've been healing you constantly, but One for All keeps destroying your body just as fast. Paralyzing you was the only way to remove your pain. I tried to take your quirk back when I first removed you from the hospital. You had so little will to resist, on all the pain-killers they'd given you, I could have succeeded. But as soon as I started to remove the quirk, I felt your body crumble. I tried to warn you before. One for All is a parasite. It's taken up root deep inside of you. I can no longer take it without killing you. Your body is past any healing. No matter if I remove the paralyzation or not, you'll never walk again. All I can do is erase your pain."
It was too much to bear. Izuku wailed like a baby into his father's arms. Emotion rocked him like a boat in a typhoon. He sweated all over. A panic shook his body that he could not move to let out. Even breathing had become difficult and labored. Between sobs, he forced out, "Please…just let me die."
"Never." More steel than contained in the vault lurked behind that one word. All for One cradled his child in his arms. "Look at it this way, ducky: when I'm looking after you, you're distracting me from my business. Right now, that makes you the most heroic person in the world."
Izuku screamed until his throat gave out.