Work Text:
Izuku ducked and held in a whimper. This was dangerous, much too dangerous. All Might had told him to run and not look back, to never stop running or hiding and to never, never use the new Quirk he had placed inside his young, fragile body. And Izuku had run, until he had heard the sounds of battle behind him. He couldn’t leave All Might, not when he knew the man was dying. Even if All Might was ready to sacrifice himself to try and bring All for One down permanently, he wasn’t ready to lose the closest thing he’d ever had to a real father. So he’d come back, and was now in danger of being killed by debris.
There was an especially loud crash, then the dust began to settle. Izuku was too afraid to peak his head up to see what had happened. Was it over? Which one was left standing? He covered his mouth and closed his eyes, shaking and listening.
“Did you really think you could keep it from me?” A low voice echoed across the crumbling landscape. “After all the ones who came before you, did you think that I wouldn’t end you the same way I ended them?”
Izuku’s racing heart stopped. That wasn’t All Might’s voice.
There was a weak cough that he recognized. All Might was still alive! At least for now. Maybe if he could distract All for One then they could get away-
“You don’t have it anymore?” All for One’s voice cut off his thoughts. Izuku shuddered. He sounded angry.
All Might answered with a weak laugh. “Like I would let you take it. You’ll never get your hands on it.”
All for One tsked. “If you don’t have my brother’s Quirk, then I have no need to keep you around any longer. Should I torture you to tell me what poor soul you gave it to, or just kill you now and start my search before they get too far away?”
“It’s gone.” All Might coughed louder, sounding worse than Izuku had ever heard him. “For good.”
“I see. It appears that you’ll take the secret to your grave, so there’s no use in torture.”
He was going to kill him. All for One was going to kill All Might. He had to stop him, had to save him, had to-
“No!” Before he knew what he was doing, he was standing between All for One and All Might, arms shaking as he held them out to shield his teacher. “Don’t hurt him! Leave him alone!”
“Izuku!” All Might gasped, between his coughs. “No!”
All for One was towering over them, his mask cracked just enough for Izuku to see one of his red eyes. “Ah, there it is. How convenient of you to come to me, for once.”
All Might managed to sit up, pulling Izuku back. “No, no, Izuku, no! Why are you here? Why didn’t you run?”
“D-Don’t kill All Might!” Izuku screamed, heavy tears running down his cheeks and collecting dust as they rolled. “Please, p-please! Don’t kill All Might!”
“This one is so little.” All for One mused, bending forward a little. “You called him Izuku? A strange choice… but my brother has always been trying to catch me off guard.”
“Go away! Leave us alone!” Izuku shrank back into All Might’s embrace. The blood from All Might’s wounds was starting to soak into the back of his shirt. He needed to get All Might somewhere safe as quickly as he could. Was there a hospital close enough? How soon could he call for help? Would help come in time if he did?
A large hand descended from above, plucking him right out of All Might’s arms by the hood of his jacket. Izuku shrieked with surprise and fear, legs and arms flailing. He stiffened when the villain held him level with his face, his visible eye pinning him down.
“Got you.” The villain said softly.
Izuku screamed. He felt something inside him crackle and try to do something, but he didn’t know what or how or-
“Relax, little brother.” All for One pulled Izuku into both arms, hugging him to his chest. “I’m not going to hurt you.”
Izuku tried to scream again, but it was hard to breathe. He had to get away, had to get back to All Might, had to call for help, had to- had to-
All for One’s hand started rubbing his back, bringing him to his senses enough to get his scream out. He struggled against the large arms, but it was like he was fighting a mountain. All for One was talking softly, something about, “all this time” and “be okay” and “keep you safe.”
“All Might!” Izuku cried, squirming harder. “All Might, make him stop! Please, please stop!”
“Let’s get you home, brother.” All for One said, seeming to agree.
“No!” Izuku tried to climb out of his arms as he turned around, carrying him with him. He didn’t know what All for One meant by that, but he didn’t like it. He didn’t like the idea of going anywhere with the villain. He could see All Might over the man’s shoulder, trying to stand, coughing up blood, reaching after him, calling his name. “All Might!” Izuku screamed back, trying to reach for him as well. “I don’t want to go! All Might, All Might!”
A cold, black mist enveloped them, taking All Might out of sight. Izuku screamed louder, fighting harder to get back to him. All for One just gave him a small squeeze and didn’t stop to look back.
***
Izuku sat nervously on the bed, trying to focus on taking deep, slow breaths. He didn’t want to have another panic attack. It was hard, especially with all the stress and fear. There were no windows, so sometimes he would feel extremely claustrophobic. The pressure was overwhelming, pressure that was about to walk through the door any moment.
As soon as he thought it, the large metal door shifted and swung inwards. Izuku tried to stay calm, but still pulled his legs up and slid back against the wall. He stared at the checkered pattern of the bedspread as footsteps came towards him. A shadow fell over his figure, making him flinch. Very slowly, he looked up until his eyes met the face of his captor- All for One. Tall, terrifying, and smiling at him with all the warmth of a loving caretaker.
“Good morning, Izuku.” All for One said in the same gentle, playful tone he always used. “You’re already dressed! Did you sleep well?”
Izuku swallowed hard and shook his head.
“No?” All for One sat next to him. Izuku felt his heart rate spike and edged away. “What’s wrong?”
“It’s not… comfy.” Izuku averted his eyes again. He missed his own mattress, the smell of the bargain laundry soap his mother used to clean his bedding, the comfort of looking out the window at night… Even if he managed to forget about all his other worries and fears, he could never get over that one.
“I’ll get you a new mattress.” All for One promised. He reached over and gently ruffled Izuku’s hair. “Sleep is important for growing boys. I want you to be healthy.”
Izuku bit down hard on his lip to hold in a scream. A small whine came out instead, along with a set of tears that he was quick to wipe away. All for One watched him and continued to pet his hair for another minute before he lifted his hand away.
“I brought you breakfast.” He offered Izuku a tray of toast, rice, eggs, and chocolate milk. “I want you to eat as much as you can.”
Izuku stared at the food and slowly shook his head. He couldn’t eat right now. He was too stressed. He would just start choking or throwing up or maybe even something worse if he tried.
“Izuku, you know that hunger strikes aren’t allowed.” All for One lowered his voice. Izuku whimpered at the threat, still staring at the food.
“N-No! I’m n-not- I’m just- I don’t feel good.” He stuttered, more tears spilling over his eyes.
All for One let out a heavy sigh. He got off the bed and knelt in front of Izuku so they were on the same level. “You need to eat, Izuku. You’ll get sick if you don’t.”
“I don’t want to.” Izuku cried, meeting his eyes. “I want to go home. Please, let me go.”
“I’m not letting you go, little brother.” All for One replied firmly. He caught Izuku’s hands and started massaging his palms. “I know you’re tired, but you need to do as you’re told.”
Izuku shook his head back and forth, unable to break eye contact. “Please. Please.” He couldn’t think of anything else to say. He couldn’t even try to pull back. He was about to have another attack, he couldn’t take it any longer. “Please.”
All for One glanced him over, sensing the oncoming panic attack as well. “Take a deep breath, Izuku. You’re hyperventilating. You’re all right, you’re safe. Calm down, little one.”
Izuku wanted to scream, but he did his best to listen instead. He followed All for One’s instructions until the urges had died down. He was left gasping and crying, but thankfully his emotions were back under his control. He could barely move, and didn’t fight back when All for One picked him up and carried him to the table.
“Five bites for me, little brother.” All for One said, laying the food in front of him again. “Can you do that for me?”
Izuku sniffled and shook his head. He was still feeling overwhelmed.
“Three bites then, one at a time. Maybe you’ll work your appetite up again.”
Three bites. He could do that. It was a start. Izuku reached a shaky hand for his utensils. He knew he needed to eat, knew that he’d lost too much weight already. But having All for One watch him eat- no, he wasn’t going to think about it. He wasn’t going to turn around. It was just him, and if he closed his eyes while he chewed, he could pretend he was somewhere else. Anywhere else. Anywhere but here.
***
By the time lunch had rolled around, Izuku had made himself dizzy pacing around the room. He had dimmed the lights- with no window it was much too scary and dark if he turned them all the way off- and was laying down on the bed. Sometimes he was able to distract himself with the puzzles, books, and games, but the morning had left him too high strung to indulge in those activities. He had tried one, but then remembered how All for One had forced them to build the puzzle together and quickly abandoned it in favor of pacing himself in circles.
It had been a long time since All for One had brought him here. At least a month, he wasn’t sure exactly. But based on the number of presents he’d been given, a month sounded about right. A whole month of being locked up, touched, fawned over, called little brother all the time. His panic attacks were getting more frequent now, often caused by that awful phrase. He wasn’t All for One’s brother. He knew that First had died a long time ago. All Might had told him the story once, about how All for One and One for All had fought and how all of First’s successors had been hunted down. All for One wanted the Quirk back… but he hadn’t asked Izuku to give it to him. Not once. Izuku was having doubts. Was it really the Quirk that All for One missed? Or was it the holder? Either way, he didn’t like being used as a substitute.
The vault door opened and All for One came back in. He didn’t say anything as he softly sat next to Izuku. He started petting Izuku’s hair again, waiting for him to respond.
“Go away.” Izuku mumbled at last, pulling the covers over his head.
“Time for lunch, little brother.” All for One said softly. “Does your head hurt?”
“Dizzy.” Izuku answered. He felt weak, shaky. He was scared. This had been happening a lot lately.
“You need to eat more.” All for One said. “I’m trying to take care of you, but you need to help me. “You don’t need to be scared. I would never let anything happen to you, little brother.”
“I’m not…” Izuku shuddered. “Don’t call me that.”
“Come on, I brought you something easy to eat.” All for One picked him up again and brought him to the table. He sat down with Izuku on his lap and tugged the blankets away until his head was exposed.
“No, no please.” Izuku begged. “I don’t want to throw up again.”
“You aren’t going to throw up. You’ll feel much better once you’ve eaten.” All for One promised.
“Let me go.” Izuku shook his head, whispering mostly to himself a plea that he knew would never be heard. “Let me go, let me go. Please. I want to go.”
“Eat up, little brother. And then I have a present for you.” All for One promised. “It’s soft and fluffy and will help you sleep better until your new mattress gets here.”
Izuku did like the idea of something soft. He wanted something comforting. Something he could hold onto so he wouldn’t feel so alone. Something warm, like a hug, like All Might would- Izuku choked as the memory of All Might flooded his mind. Was he still alive? Was he worried about him? Was he looking for him? Was he going to save him? Would they ever see each other again? All for One left him for dead, but there was still a chance-
“Why are you crying, little brother?”
Izuku shook his head. He didn’t know how to say it, didn’t want to tell him. “Let me go!” He cried instead. “I want to go home! I’m not your brother!”
“This again?” All for One growled, holding Izuku tighter. “Izuku, I thought I made it very clear. This is your home now and as long as you have that Quirk, you’re my little brother.”
“I don’t want it anymore!” Izuku cried. “I want mom! All Might! I want to go! Let me go!”
“If you keep crying like this, you won’t get your present.” All for One warned, but Izuku had stopped listening to him. He was tired and sick and didn’t want to hear another word.
***
The rest of the day was a struggle of All for One trying to console him with Izuku screaming and crying until he really did throw up. All for One fought to get him to eat again, struggled to get him showered and dressed for bed. He had finally wrestled Izuku into his pajamas, forced him to brush his teeth, and was making sure he stayed under his covers. Izuku was tossing and turning, hugging his new fluffy bunny doll tightly. All for One had given him the present in a vain effort to calm him, but Izuku refused to be settled.
"I'm not your brother!" Izuku wailed, exhausted from struggling against the villain for so long.
"Yes, you've made that point quite clearly. My brother was never as small as you, never this loud either. But you have his Quirk, so you are family." All for One let out a frustrated sigh of his own. He had tried to get Izuku to behave, but no matter how hard he tried, Izuku just wasn’t Yoichi.
"I'm not! Just let me go!" Izuku tried to kick the blankets up, but they were tucked in too securely for him to manage it.
"My brother never cried this much either... you're quite the little baby, aren't you Izuku?” All for One paused, a smile taking over his face. “Yes, that feels right. You'll be my baby, my son. Yes, I like that very much. My little Izuku..."
“No!” Izuku screamed, sounding horrified. “No, let me go! I hate you!”
All for One wasn’t listening anymore. He gathered Izuku up into his arms, cooing with newfound adoration. “It’s all right, baby. Daddy has you now, you don’t need to be scared. You don’t need to cry. I won’t let anything happen to you.”
“No!” Izuku shook his head, new sobs forcing their way out of his tired body. “No, no, no, no, no!”
“Shhh…” All for One rocked him, something he’d never done with his brother. His brother had always been too big for this kind of treatment, but Izuku was so small… “Go to sleep, baby. You’ll feel better in the morning.”
Izuku did fall asleep, but not before more screaming and sobbing and crying… All for One was used to Izuku crying himself to sleep, but he hoped that this new change in their relationship would solve that issue. He started to tuck Izuku back in bed, then hesitated. Izuku didn’t sleep well in this bed. This bed was perfect for his brother’s taste, but not Izuku’s. And he didn’t feel comfortable leaving Izuku by himself tonight. He couldn’t help but chuckle at himself as he carried Izuku up to his own room. It hadn’t been a full hour since he’d made up his mind to be Izuku’s father and he was already turning into a hovering parent. But he couldn’t help it. Thinking of Izuku as his son just felt right in a way that he couldn’t explain. One for All had come to Izuku, and Izuku had come to him, so it was meant to be.
All for One got into bed and nestled Izuku in beside him. Izuku was going to be tired in the morning after crying all day. He would probably have a headache too and would be weak from hunger. But perhaps he would eat better now… All for One had of course noticed that Izuku’s appetite declined rapidly every time he had called him “little brother”. With that title gone, perhaps he would stop stressing so much.
It had been a lot of pressure to put on the boy, All for One realized now. He was only twelve, the smallest twelve year old he’d ever seen. How could Izuku be this small? He had never properly cuddled with him before but he was suddenly afraid that he might break the child. For a moment, he was angry at All Might for choosing someone so small and fragile. If not for the Quirk Suppressant bracelets he’d put on Izuku, One for All would have torn his small body apart. But… he had forced All Might’s hand. The buffoon had likely been holding back from passing the Quirk on until Izuku’s body could handle it, but he hadn’t had a choice when he’d found him at last. Things had all worked out for the best. He was glad that he hadn’t had to miss out on any more years of Izuku’s life.
It was hard for him to sleep, thinking about how things would be different now. Instead of getting gifts that his brother would like, he needed to find out what things Izuku liked. He could bring him his favorite books and foods and talk to him about his interests. He couldn’t wait to get to know Izuku. Talk with him, cuddle with him, read with him, play with him. His son. Izuku was his son .
All for One was mesmerized by him, petting his freshly washed and dried curls out of his face. So small… How was he this small? He couldn’t get over it. Izuku whimpered in his sleep and hugged his bunny closer. All for One smiled. It had been a good choice. Soft, small, cute, green… exactly like Izuku.
Izuku continued to whimper, his breath starting to quicken. “No… no, let go.” He muttered in his sleep. He was squirming, whining, having another nightmare. “Mommy… All Might… Mommy!”
“Shhh…” All for One pulled him closer. “It’s just a dream, baby. Daddy’s here. You’re okay, little one, you’re safe here with me.”
“All Might.” Izuku cried, his tone turning from desperate to depressed. “All Might, All Might, All Might!”
“Hush, sweetheart.” All for One pressed a kiss into his forehead. He hugged Izuku tighter, which seemed to calm him down a little. Izuku snuggled into his embrace, still muttering to himself. “Good boy.” All for One gave him another kiss. He loved these new bedtime kisses. He pulled Izuku’s bangs back and gave him another before resting his head down as well. “Let Daddy take care of you from now on. We’ll be a nice, happy family. I won’t ever, ever let anyone take you away from me. My precious little Izuku…”