Once More, Again:

Hisashi Shigaraki had been in a state of numbness ever since his younger brother died. Being All for One had lost its appeal. He no longer had anyone to lord it over, to persuade, to protect. It had been years since he'd made a move to expand his criminal organization. He simply kept operations running, coasting by on his reputation.

When he spotted his brother's successor, it hadn't even seemed worth the effort of chasing down the pest. But the Second One for All User had attacked him instead of running away. With his last dying breath, the Second had accused him of killing his own brother.

Hisashi still burned with fury at the memory. The fool understood nothing. He'd tried so hard to keep Yuuto alive. Was building a person-sized bank vault cheap? Yet some insignificant, explosive idiot dared accuse him when it had been all been the Second's fault anyway. He should have killed the pest slower.

But the cruel words had struck their mark. Since then, Hisashi hadn't been able to work up the will to slay another hero. He barely even felt like leaving his bed.

He became obsessed with finding a quirk that traveled backward in time.

In every single timeline, his younger brother's death sent All for One into a depression. In most timelines, he eventually rediscovered the joy of villainy and returned to conquering Japan. In this one, he actually found a time-travel quirk.

The deal took place in a dingy warehouse. Hisashi didn't want to risk his wool suit by sitting in one of the plastic chairs. He wrinkled his nose at the musty smell and glared at the weasel-faced man. "You'd better be telling the truth about your quirk."

These days, even Hisashi's threats were half-hearted. But this one was still enough to make the scrawny man tremble. He said, "My ability allowed me to travel back in time to my younger body, with all my memories intact. But it only works once. That's why I'm willing to sell it to you."

An insanely powerful ability despite the one-time limitation. Such a power could allow the user to build an empire. Clearly, this fool had squandered his gift, judging by the ragged shape of his clothes and the calluses on his hands. What kind of idiot couldn't manage to become rich even with knowledge of the future?

Hisashi inclined his head at a minion, who stepped forward with a briefcase of money. If the time-travel quirk turned out to be a lie, he could easily return and take back his cash. A matter of this importance was worth the risk.

While the beggar was still counting bills, Hisashi grabbed his head and took.

The weasel-faced man whimpered. Hisashi hissed in triumph as he felt the power settle under his skin. Without hesitation, he used it.

The world turned white.

Hisashi opened his eyes. He sat in a plush office chair. Immediately, he moved his mouse to the bottom of the computer screen check the date. He'd traveled back nearly two decades.

Part of him couldn't believe it. He glimpsed his reflection on the shiny screen. His hands went up to touch his face, feeling fewer lines and longer hair. He was nineteen years old.

Ever since he'd learned of the time-travel quirk, Hisashi had contemplated what point in his life he would want to return to. The earlier the better in terms of using his present knowledge to take over Japan. However, Hisashi had no desire to relive the poverty of his early childhood. The notion of dodging his father's fists again felt degrading.

He'd picked nineteen years old because he'd just been starting to build his criminal empire. His worthless parents were dead. He currently had enough power to protect himself, but it was early enough for him to use his knowledge of quirk locations, political events, and financial movements to become so much more powerful this time around.

In a few weeks, there would be a gang war. Several of his lieutenants would betray him. This would lead to Hisashi being briefly kidnapped by traffickers and his younger brother being shot. That incident had had lifelong ramifications for Yuuto's health, so he'd picked this date with an eye to preventing it from ever happening.

Yuuto.

Hisashi's breathing came faster. His hands shook. He wanted to see his little brother so badly, yet the idea terrified him. Blood blossoming on a scrawny chest. Pale hair falling in all directions on the dirt.

No. That hadn't happened yet. Yuuto was still alive. He must be.

The window showed it was late at night. Hisashi walked slowly down a hallway no longer familiar to him. Because he'd lived in this place for so many years, he could just barely remember the route to his younger brother's bedroom. Reaching a door covered in sparkly star stickers, he pushed it open.

Eleven-year-old Yuuto lay tucked under a bright rainbow bedcover. He stirred, letting long white hair fall over his face.

Hisashi's legs moved without conscious command. In a flash, he'd gathered his younger brother into his arms. He marveled at the warmth and smallness of the child's body.

Yuuto cracked one green eye open. "Whaz up?" he mumbled.

Both the sight of his younger brother's eyes and the sound of his voice were like daggers into Hisashi's heart. A tear trickled down his cheek.

Yuuto's head shot up, now completely awake. "Big brother? What's wrong?"

In spite of himself, Hisashi wept harder. He rocked back and forth. He knew he was alarming his little brother, but he couldn't stop.

"Did you have a nightmare?" Yuuto asked.

In a strangled voice, Hisashi said, "Yes, I did. A horrible nightmare. One which will never, ever come true. I won't let it."

Yuuto cocked his head, puzzled. "Then I guess you can sleep with me. After all, you always let me sleep with you when I have nightmares." He proclaimed this as if making a generous offer. One small hand patted his older brother's back.

Hisashi clung to his little brother all through the night.

Come morning, it was extremely hard for Hisashi to let go of his brother. He only forced himself to leave because he needed to go purge the traitors who would later prove a threat to Yuuto's safety.

First, of course, he installed several cameras in Yuuto's bedroom and tutoring room so he could reassure himself with a constant livestream. He should have done that from the beginning. If parenting books didn't typically recommend 24/7 surveillance, that was only because those so-called experts had never tried to parent Yuuto Shigaraki.

Removing the traitors proved both swift and satisfying. Then he had time for a brief afternoon jaunt. Japan's first batch of professional heroes would have to be different people this time around—because he'd already stolen every single one of those future heroes' quirks. Such a shame for them. Dozens of bright, powerful new lights burned under his chest. He hummed a happy tune as he headed home to invest in the stock market.

Back in the future, Hisashi had memorized years of stock movements. He estimated it would take him a matter of months to become the richest man in Japan. Additionally, he had so much excellent blackmail material! Time to send a few messages to powerful politicians. Then he'd start recruiting some people he knew would be useful in the future.

Someone knocked on his door. Yuuto called, "Big brother?"

Hisashi swiveled around. "Come in."

Yuuto padded across the office carpet, his eyes lowered nervously. "Do you have time to eat dinner with me?"

Although Hisashi still had many plans, none of them were urgent. He couldn't resist that shy request. "Of course."

"Really?" Yuuto's head shot up. He beamed.

The worshipfulness in that gaze unnerved Hisashi. Yes, there had been a time when his younger brother had looked at him like he hung the moon and stars. By the end, he'd gotten nothing but sickly and hateful stares. This…this was nice. His chest tightened.

Oblivious, Yuuto chattered on. "You've been so busy lately. I'm glad we can finally have a meal together."

When he'd been nineteen, Hisashi vaguely remembered being preoccupied with his criminal empire and too cool to seek out his younger brother's company. More the fool he'd been, since later he'd ended up begging for a scrap of this current affection. Time to savor his stolen fruit. He stood up. "I'll make sure to save time for our family dinners from now on."

"You'd better, if you expect me to keep chasing your nightmares away." Yuuto's eyes danced with mischief. "A scaredy-cat like you needs me."

"Why, you little scamp." Hisashi ruffled his brother's hair.

Yuuto didn't pull away. Instead, he leaned into the touch. Hisashi could barely restrain a surprised gasp.

As they walked down the hallway, his little brother shyly reached out, trying to hold his hand. Of course Hisashi let him. Such a tiny, weak, fragile hand. In the dining room, he ventured to place a kiss on his younger brother's forehead before letting go.

Yuuto stood on his tiptoes and kissed his cheek back.

Hisashi felt like he'd been struck by lightning. A horrible fear came over him that he'd lose this all over again. Was there a way to prevent their fight from occurring?

He still didn't know what to do to change Yuuto's mind from the original timeline. People had so many more variables than stock market fluctuations. Could he prevent Yuuto from ever finding out about his villainous business? Unlikely. Could he sway his little brother's beliefs with fewer comic books and more stories with antiheroes? Maybe if certain bad influences could be avoided, like that damn idiot his brother had picked as the Second One for All user and later died blocking a blow for…

The scrawny form lay in a pool of blood. The precious red liquid dribbled from his mouth and his chest. Green eyes stared up at the sky, blank and sightless.

Hisashi's heart beat inside his chest like a caged bird. Nothing else mattered in the slightest, if only this time he could keep Yuuto alive. He'd live with hatred if it meant he didn't end up with an urn full of ashes. It will all be okay if I lock him up even better this time.

Over dinner, Hisashi asked his brother some vague questions about his day. Yuuto complained about being pulled from public school and cooped up inside with tutors, but he was easily redirected to talking about the latest comic book he'd read. He blossomed under each bit of attention from his older brother. It was effortlessly easy to make this younger Yuuto smile. He soaked up the smallest of compliments.

After dinner, Yuuto asked, "Can we play a game?" The pure, absolute love in his eyes still stole the breath away every time Hisashi saw it.

It took all Hisashi's willpower not to immediately say yes to those cute, wide eyes. But he had parental responsibilities. He said, "Sure, once you've finished your homework."

All color drained from Yuuto's already pale face. He looked at his shoes. "Never mind."

Hisashi frowned. Were they going to have to go back their same old battles about Yuuto's schoolwork? The increasingly severe punishments that still failed to make his stubborn baby brother pick up a calculator? Although it was small in the scheme of his regrets, it still bothered Hisashi that his brother had never graduated from high school. It had been a glaring black mark on his parenting record.

Even though he wanted so badly to keep the current peace, he couldn't let Yuuto fail out of school all over again. He spoke as kindly as he could. "I'll help you with your homework. We can spend time together. Maybe it will even be a little fun."

Yuuto shook like a leaf. When he glanced up through his bangs, a look of total terror showed in his green eyes.

Nineteen-year-old Hisashi would have missed it. After all, it made no sense for a child to be scared of homework. Bored, sure. Belligerent, absolutely. But fear? Why fear? Did he need to murder a tutor?

Time to investigate. "It's your math homework you haven't finished, isn't it? Can you tell me what's wrong?"

"Nothing's wrong!" Yuuto screamed. He stamped his foot down. "I hate math. I refuse to do it. You can't make me."

Here was the defiance Hisashi had come to expect. When he'd been an impulsive teenager, this would have quickly deteriorated into a shouting match. But his adult self could detect a hint of fear behind his little brother's aggressive posturing. This made him gentle his tone. "How about you just let me look at your math homework, then we can play a game?"

Yuuto eyed him with naked suspicion. "I don't have to do my homework?"

"We'll make today a homework free day if you'll look at the problems with me." Hisashi wondered if he was making a mistake. In the past, he'd been so convinced that if he gave even a little ground to Yuuto's truancy, then all discipline would be lost. But it wasn't like his past tactics had worked. Maybe he should try something new.

Slowly, Yuuto nodded.

In the bedroom, bent over a child-sized desk, Hisashi examined Yuuto's math homework. He could see nothing wrong. If anything, surely these problems were too easy, even for an eleven-year-old.

He looked up. "I'm not sure what's wrong. You could finish this in seconds, then we could go play a game."

Again, that flash of fear in Yuuto's eyes. Very strange.

Hisashi pointed at the first question. It showed a bar graph with three bars. The question was laughably easy: which category was the biggest? He said, "The blue bar is the tallest so that's the biggest, see?"

Yuuto drifted closer. "How did you tell that?"

"How did I—" Hisashi stopped. Hadn't he answered this question before? Decades ago in the past? Back then, he'd said it was obvious, then that had deteriorated into a shouting match.

There was a painfully vulnerable look in Yuuto's eyes. Slowly, Hisashi said, "Blue is the longest bar."

Yuuto flushed. "I knew that! I'm not an idiot. I just don't feel like doing math."

How had the past Hisashi been so blind? True, he'd been a teenager, little more than a child himself. Yet back then, he'd been so convinced that his younger brother was trying to get out of schoolwork because he was lazy or rebellious.

Looking at Yuuto now, Hisashi saw a small child desperately afraid that his older brother, who he worshiped like a god, would think he was stupid.

"You can't tell which bar is tallest, can you?" Hisashi whispered.

"No-no-no-no!" Yuuto paled. "I can tell! I'm not stupid!"

"That's not what I meant. This isn't a question of being stupid." It had to be a visual issue or a learning disability. How could he have possibly missed this? What kind of failure of a parent was he? Hisashi took a moment to figure out what to say. "Sometimes people perceive the world in different ways. These math problems are presenting information to you in a way that you can't understand. You're not the problem here."

Yuuto whispered, "I'm not broken? Math is broken?"

"That's exactly right." Hisashi gave his little brother a pat on the head. Yuuto leaned into the touch. Hisashi tugged him closer. "Forget about the broken math problems. You don't need to do them. We're going to have some ice-cream and play some games. Then tomorrow, I'll try to figure out how to change math into something you can understand."

"You're going to fix math?" Yuuto stared at him in awe. "Whoa. You really can do anything, big brother."

"Of course, I'm the best. Haven't you figured that out by now?" Hisashi beamed.

Dyscalculia. Hisashi stared at the diagnosis on the paper in his hand, once again cursing his past self as a fool. How had he possibly missed this? Everything fit: a mathematical disability causing difficulty in understanding numbers, performing calculations and spatial reasoning. How much pain had poor Yuuto been through the first time around? His fist clenched, crushing the paper.

Of course, there were other people even more to blame than him. Hisashi kicked the body of the tutor lying on the floor. The corpse smacked the desk leg with a wet thud.

He had no remorse for his hasty crime. Unlike his teenage self, Yuuto's tutors had no excuse for missing something so important. What had he been paying them large sums of money for? He'd entrusted them with something precious, and they'd failed him. Yuuto had seemed happy upon learning he'd never have to see his former tutor again, which confirmed to Hisashi that he'd done the right thing.

Hisashi pulled out his phone and started searching for math teachers with experience teaching students with dyscalculia. Preferably ones without too many relatives, just in case he had to deal with another such situation.

Yuuto was definitely getting cheerfuller. His cheeks had more color, and he was doing better at his lessons. Hisashi wondered if part of it might be that he'd started talking his little brother to the park on a daily basis. Yuuto definitely thrived on both sunshine and interaction with other kids.

It worried Hisashi, because he might not have the time to escort his little brother every single day once he launched his first major assault on the government. But to let Yuuto go without him, no matter how many bodyguards he took, would be unthinkable. He'd already learned the dangers of entrusting his brother's safety to anyone besides himself.

When he'd first arrived in this time period, he'd had the resolve to protect Yuuto no matter what, even if the child ended up hating him for locking him up. But in the face of the current little brother who absolutely adored him, Hisashi couldn't even imagine losing that again. There had to be another way. With only one shot to travel backward in time, he couldn't afford to let down his vigilance. Nor could he quite bring himself to purchase a vault. In the short run, his solution was to stick by Yuuto's side as much as possible.

They'd settled into a routine where Yuuto did his homework lying on the floor of Hisashi's office. A welcome change, that his little brother actually did schoolwork without being forced. Sunlight leaked through the bullet-proof windows and cast shadows on the chestnut desk and dual computer monitors.

From his place on the carpet, Yuuto cast a furtive glance in Hisashi's direction. He rummaged around in his backpack. Then he walked over and gave his big brother a hug.

Hisashi, busy typing, reached one hand over to pat Yuuto's shoulder.

In a swift movement, Yuuto fastened one end of a handcuff to Hisashi's wrist and the other to the desk leg. Then he leapt backward, out of reach.

Hisashi stared at the cuff around his wrist. A quirk suppressant cuff. Betrayal cut through him like the sharpest winter wind. Had the Cain Instinct truly started at such a young age? Hisashi had only thought about locking his little brother up—he hadn't actually done anything yet! Hadn't they been getting along so well lately? Surely it wasn't possible that Yuuto had always hated him?

Yuuto ran to his backpack and pulled out a gun. Aiming, he said, "Tell me where my real brother is, or I'll shoot you in the leg."

Hisashi's dark thoughts cut off sharply. "Your…real brother?"

"Did you think I wouldn't notice the difference?" Yuuto's hands shook. His face had lost all color. A hint of tears glistening in his eyes. "Even if Hisashi is an asshole, he's my asshole. He's saved me so many times, so I'm going to save him this time. Give my big brother back."

Hisashi's hurt feeling faded away, replaced with a euphoric relief. Of course Yuuto had become suspicious. He couldn't blame the child, not when this was only proof of how much he cared about his big brother. If Yuuto's personality had completely changed overnight, then Hisashi would have started wondering about imposters and mind-control quirks too. His little brother wasn't stupid, and he'd been wrong to ever think so.

"Say something," Yuuto hissed, terror leaking into his voice. He waved the gun.

Hisashi didn't feel even the slightest bit worried, because Yuuto hadn't removed the safety from the gun. Clearly he didn't know how. Still, this wasn't bad for a first murder attempt. Hisashi would teach him better later.

Smiling, Hisashi said, "It really is me, Yuuto. I picked up a new quirk."

Yuuto stared at him. "A quirk that makes you nicer to me?"

Yikes, how bad had he used to be? Hisashi vaguely remembered spending his teenage years finding his baby brother annoying and enjoying riling him up. Maybe he'd been a little bit of a bully. Not overly enjoying this self-examination, he decided to drop it.

"I traveled through time. I seem different because I'm two decades older mentally."

Yuuto shifted from foot to foot, biting his lip.

"Would a fake know how I first discovered my quirk? A man breathed fire at you, and I jumped in-between." Hisashi met his little brother's eyes, willing his sincerity to be conveyed. "I would have died for you without hesitation back then, and I still would. I went back in time for you."

"Big brother!" Running forward, Yuuto clung to him tightly. "Thank goodness," the child sobbed into Hisashi's shoulder. "I was so afraid something bad happened to you."

"There, there. It's okay." Hisashi patted him on the back with one arm. "I'm way too strong for that. I'm not going anywhere."

Later, after Yuuto had dried his tears and fished the handcuff key from his pocket, he asked, "Why did you travel back in time, big brother?"

Hisashi chose his words carefully. "I came from a bad future. One I'll ensure doesn't happen again, no matter what." His grip tightened around his baby brother, only stopping after a small cry of pain.

OMAKE TIME!

Omake: The Family Who Villainizes Together Stays Together

Hisashi: Look, my little brother is just eleven years old and he's already trying to shoot someone. I'm so proud.

Hisashi: Admittedly, it's me he's trying to kill.

Hisashi: But I'm going to choose to view this as a step in the right direction on his path towards villainy!

#

Omake: Vaulting Instinct Currently Set to Maximum

Yuuto: (Breathes wrong.)

Hisashi: I knew the outside air was too much for you to handle. Get into the vault.

Author's Note: The future is still full of minefields since Yuuto will one day find out about his brother's villainous activities. Maybe that conversation will go better since the relationship between the brothers is stronger in this timeline. On the other hand, Hisashi's vaulting instinct is on a hair-trigger after he watched his little brother die once. And he's gotten a lot more powerful due to his future knowledge. Yuuto will be lucky if his older brother isn't Emperor of Japan by the time he's ready to rebel.

Next up: Another Custody Battle epilogue oneshot. Hisashi visits Izuku's school and butts heads with a snooty parent. Will Izuku be able to stop his dad from slaughtering his way to the top of the PTA?