Author's Note: Credit for this prompt goes to Ilentari, a masterful Dad for One writer at over at Archive of our Own. Additional credit to bitsinboots for coming up with some of the ideas I used in this story.
Chapter One: Who's the Older Brother Now?
Hisashi Shigaraki placed a hand over his younger brother's eyes, ignoring the screaming and cursing. The frail, starved youth could barely put up more than a token struggle. The hands trying to push him off felt like a child's blows.
Really, Yuuto had always been exceptionally foolish. These pointless escapes, pathetic attempts to thwart his plans, and worrying refusal to eat—they had to stop. And All for One had obtained the perfect ability for that purpose.
Hisashi had almost given his pathetic little brother a stockpiling ability to strengthen his ill body, but then he'd found something even better. One of his followers had found a woman whose metahuman power forced her to constantly learn valuable moral lessons. She couldn't turn off her ability. She'd begged him to take it away. Always convenient when the sheep made it easy for him.
Ideally, Yuuto would learn about the importance of family and the futility of picking fights with his much stronger older brother. Then maybe Hisashi would give him the stockpiling ability next and they could rule together as a family. What was the worst that could happen? If he didn't like the effects, he'd just take the power back.
"This is for your own good." Red light shot from Hisashi's palms. Yuuto screamed one last time, more in rage than pain.
Then a massive blaze of light made the world turn white.
Hisashi blinked. He knelt on the floor. A hand covered his face. White hair much longer and straighter than his should be fell over his eye. And he felt so hungry his stomach might be about to cave in.
He looked up to see his own body looming over him.
His twin self gaped at his hands with their red marks. He looked around at the vault's steel walls. He whispered, "Hisashi?"
That was when Hisashi realized the horrible truth. "Yuuto? We've swapped bodies!" He had many more things to say on this terrible topic, but he doubled over coughing.
"It's okay." Yuuto-in-his-body patted him on the back. "Don't try to talk. Breathe deeply. The pain will pass, I promise."
A trickle of blood ran between Hisashi's—Yuuto's?—fingers. His chest burned. Each breath felt wet and strained. His head felt like someone had taken a hammer to it. If this was how Yuuto felt all the time, he wondered how his little brother managed to be so annoyingly energetic, particularly when it came to poking his head into his long-suffering older brother's business.
This sucked. The karma ability had been a complete bust. Hisashi tried to pull it back while Yuuto was still touching his back.
Nothing happened.
Hisashi's mind went blank. He should have guessed from the beginning. But the truth had been so horrifying, he'd tried to block it out.
His foolish younger brother now had All for One.
Judging from the grin on Yuuto's face, he'd reached the same realization. "Hey, little brother."
Hisashi glared. "I'm your older brother, and I demand you treat me with respect!"
"With what power?" Yuuto raised an eyebrow. It felt strange, seeing that impish expression on his own face.
Hisashi snarled, "The metahuman ability I gave you forces you to learn moral lessons. The effects wear off once you've learned whatever lesson the power deemed you to need the most. This is temporary! Once I get my power back, I'll—"
"You'll what? You've already done your worst to me. I fail to see how pissing you off any further would worsen my situation." Yuuto gestured at the barren walls of the bank vault.
Hisashi froze. Unfortunately, his pathetic little brother had him dead to rights. He wasn't going to torture or kill his only family member, and they both knew it.
Yuuto's grin widened. "Do you know what I'm going to do while I still have your body? I'm going to give away all the metahuman abilities you've collected to poor, deserving orphans."
"You idiot!" Hisashi shrieked. "Do you know how long it took to steal all those?"
"Yes, and that makes it even better. You know what else? I'm going to become a hero." Yuuto leaned down and purred, "I'm going to make your face so famous that you'll never be able to escape your heroic reputation no matter what you do later. You'll never be taken seriously as a villain again."
Infuriated past all reason, Hisashi lunged for his little brother.
Holding him off with one arm, Yuuto said, "Give me one good reason not to leave you inside this vault like you did to me."
Hisashi shouted, "Because you won't last a day in my body dealing with my life! Don't you get it? The people I work with are dangerous. You'll get your dumb self killed immediately!"
"Insults? Rejected. Enjoy your vault." Yuuto called, "Minions?"
The round vault door started to open. Hisashi's men entered, one holding a plate of food with a metal cover to keep it hot. Two more men pushed Hisashi down to the floor.
"Careful, he's fragile." Malice gleamed from Yuuto's smiling white teeth. "See you later, foolish younger brother. Maybe you'll learn a valuable lesson from this." He stuck his chin in the air and haughtily ordered, "Heel." The men fell in behind him.
"Wait! I'm actually—" The vault door closed with an unpleasant boom.
Hisashi sank to the floor, muttering, "I don't sound so snooty. Idiot."
Yuuto was flying high on adrenaline and spite. He knew he would face the consequences if and when he switched back with his older brother. But he didn't care. Time to wreck as much damage as possible on All for One's organization while he had the chance.
He had no idea the names of the men following him. Luckily, he doubted his older brother remembered the names of his minions, either. Trying to sound like an arrogant bastard who believed himself to be rightful ruler of the world, he ordered, "You! Assemble all of my top people in the conference room."
"Your top people?" The man blinked. "Who does that mean? Which conference room?"
Yuuto sighed as if disappointed. The man paled.
Being taller made it easier to look down on people. Raising an eyebrow, Yuuto said, "Use some initiative. Figure it out. And I mean whichever conference room he—" he pointed at the other man "—can prepare fast enough."
The terrified men fell all over themselves to assure him they'd do as he ordered. Yuuto smirked. He could get used to this.
His body felt wonderful. No pain in his lungs. No weakness in his limbs. No nagging sensation he was about to run out of energy like a gas tank with only one bar left. He almost felt bad for his older brother, stuck with the pain he so keenly remembered. After all, he'd been living with his illness his entire life. He knew how badly it sucked.
Then Yuuto remembered the past month he'd spent locked in a bank vault, and he didn't feel guilty in the slightest.
He didn't know what lesson he was supposed to learn in order to cause the ability to wear off. But he hoped he could avoid learning it for as long as possible.
Hisashi felt famished. He fell upon the dinner plate immediately. It took conscious effort for him not to sip the udon so fast it burned his tongue. He reminded himself that his younger brother's body had been without food for some time, so if he ate too fast, he might hurt himself.
Why did Yuuto have to starve himself like an idiot? What purpose did it serve except to cause him unnecessary suffering?
It wasn't as if Hisashi had set out to be cruel. At one point, this room had been stuffed with comic books and games. He'd removed them in punishment after his foolish little brother had set the place on fire and tried to strangle him with a noose made from book pages.
Yes, everything was all Yuuto's fault. Hisashi had only justly punished his younger relative's pyromaniac behavior. He didn't deserve to be stuck here in the slightest. The metahuman ability had failed to deliver proper karma as promised.
He wiped some broth off his lip and looked around for anything useful.
Unfortunately, Hisashi had put great effort into creating a prison capable of holding his escape artist brother. He'd stripped anything sharp and pointy from the room. All that remained was a bed bolted down, a table for eating, and a bookshelf recently stripped of all entertainment. He'd even had to coat the hard surfaces in the bathroom with rubber. The vault door had no way to open from the inside.
If only he could talk to his followers, then surely he could convince them of his true identity. Unfortunately, after Yuuto had started singing "I know a song that gets on everybody's nerves" on repeat, he'd soundproofed the vault.
Hisashi was stuck in here.
A ventilator overhead whirred obnoxiously, making it hard to think. His head pounded with each sound. Every part of his body ached. He coughed again.
He felt terrible. If his little brother's ill body felt like this all the time, where did his maniac energy come from? Stubbornness? Masochism? Spiteful will to make his older brother suffer? All Hisashi wanted to do was lie down on the bed and sleep for the rest of his life.
He tried to resist his exhaustion. But there was nothing to do in the horribly empty vault. No distraction from the pain tormenting his chest and throat. Before he collapsed to the floor, he managed to stagger to the bed and lie down.
The position of All for One's bodyguard was prestigious and powerful. Even so, Kenjiro Ui knew he'd ended up with the job partly because everyone else was scared to stay so close to the boss. Although a great man, he could be…capricious.
Yet Kenjiro had never seen anything like today.
The legendary All for One wrote on the whiteboard. "I'll be assigning you points based on the number of good deeds you can commit. Helping an old lady cross the street: one point. Rescuing a cat from a tree: three points. Stopping a mugging or robbery is worth twenty points."
One of followers gathered around the table raised a hand. "Master, is there a point to this? Is it part of some plan of yours?"
All for One grinned in a way that frankly made him look unhinged. "Yes, exactly. It's all part of my plan. None of you are important enough to know what my plan is, of course. Any questions? Just kidding, I don't take questions from peons."
Everyone in the room quickly closed their mouths.
"Now, onto the fun part of this meeting." The cheerful promise in their boss' voice made the others shudder. "Next, I'm going to teach you how to meditate."
"Meditate?" Kenjiro whispered in surprise.
All for One glanced at him. Those piercing eyes made him shake. The wicked smile widened. "You're going to learn how to become one with the universe. Here, I found a video on my phone."
It soon became evident that their glorious leader was not, in fact, joking. All for One forced them all to close their eyes and hold their hands in a lotus position, as if they knew as little about yoga as the middle-aged white woman in the video. He walked around the room, smacking anyone who tried to speak or open their eyes.
As soon as All for One's back was turned, the man sitting next to Kenjiro whispered, "Doesn't the master seem different to you?"
Yes, but Kenjiro didn't want to admit it. "I'm sure there's a secret, incredibly clever plan."
"Which requires us to meditate?"
Kenjiro sighed. "You know he sometimes gets odd notions in his head. Like that weak stockpiling ability he absolutely had to obtain but then suddenly lost interest in, building bank vaults, and stalking his younger brother." Admittedly, the younger brother thing had gone on for quite some time now. "Just play along until he finds a new distraction."
All for One appeared behind him in a flash. "No talking!" He whacked Kenjiro over the head with the whiteboard marker. "Obtain oneness with the universe!"
Kenjiro closed his eyes and endured.
When the video finally ended, everyone breathed a sigh of relief. But they'd let down their guards too soon.
"Now you're ready for the next exercise to clear your minds of all that nasty negativity." All for One held up another video. "Time to learn Zumba!"
The various criminal overlords gathered around the table stared at him.
"Did I stutter?" Malice filled All for One's tone. "Get up and start dancing or I'm about to murder some people."
"Never mind, he's still the same as ever," Kenjiro's seatmate sighed as he stood up and started waving his arms.
All for One marched around the room, correcting the dancing posture of the most dangerous criminals in Japan. Waving his marker, he barked, "More energy! More passion! I want to see you flitting like beautiful butterflies!"
The criminal leaders looked miserable. Well, all except one. Machia twirled past, waving his arms and crying, "This is so much fun, Lord!"
All for One's eyes fell on Kenjiro. The gaze was extremely unfriendly. As the music kept playing, the supervillain asked, "Aren't you the bodyguard who subdued me—uh, my pathetic little brother—last time he escaped?"
Kenjiro snapped to attention. "Yes, master! My pleasure, master!"
"Did I ever give you a reward for that?"
"Yes, you did. You said it was hilarious how I rubbed his face into the dirt, so you gave me a huge bonus."
All for One's eyes became even more evil. "I have another reward for you. A job only you can do!"
"Anything, master." Kenjiro shook in terror.
All for One slung an arm around his shoulder in a mockery of friendship. "I'm in desperate need of a circus clown to entertain children."
Kenjiro wondered if maybe it was time to find a new job.
Hisashi didn't know how long he'd been trapped inside this cruel bank vault. It might have been hours. Maybe even days. Why hadn't another meal come by? He'd been hoping for a chance to talk to one of his followers or maybe even overpower one of them. But he'd been left alone. Surely Yuuto wouldn't be so cruel as to starve him? He'd never gone that far when he'd been the captor! His little brother had been the one to refuse to eat!
Oh, right, there was a clock over the bookshelf. Hisashi overcame the weakness in his legs to stand up and walk over.
"Half an hour!?" he shrieked. No way. It wasn't possible. Surely it couldn't have only been half an hour since he'd been in here. Maybe his little brother had tampered with the clocks. Admittedly, that sort of subtle cruelty didn't sound like Yuuto at all.
The leftover broth in his bowl still felt warm. It really had only been half an hour.
Hisashi felt faint. How was he going to get through this ordeal? What had he possibly done to deserve this? Besides all the crimes and murder, of course.
This room felt both stuffy and drafty. He could have sworn he'd kept it warm for his little brother, but he still shivered. Maybe his sickness made his body cold.
After tossing and turning, he finally managed to fall asleep.
The next morning, Hisashi woke up to find breakfast on the table. He'd missed his opportunity! Now he'd have to wait another meal for someone to enter the vault. To make matters even worse, his head hurt and his throat felt congested. When he rubbed his mouth, he found a trickle of dried blood from his coughing late at night. Although he wolfed down breakfast, his body still had very little energy.
Being Yuuto felt awful.
The more Hisashi had nothing to do except watch the clock, the angrier he got. At least he came by regularly to gloat over his younger brother. Yuuto seemed to have stuffed him in here just to ignore him. And Hisashi hated being ignored.
This was all Yuuto's fault for rebelling so many times his loving older brother had been forced to strip his room of all entertainment. None of this ever would have happened if his foolish little brother had been more obedient. Then Hisashi wouldn't have been forced to give him this inconvenient karma-related ability and accidentally swapped their bodies.
The original owner of the ability had warned him the moral lessons often took bizarre, humiliating, and unpleasant forms. Hisashi had just figured that would be his little brother's problem. He'd never imagined he'd be caught up in it.
Unfortunately, even if he could get out of this horrible place, his rebellious little brother would never give him his precious All for One back. The only way to reacquire his rightful power would be to satisfy the onerous conditions imposed by this extremely stupid ability.
What moral lesson had Yuuto been supposed to learn from the body swap and why had Hisashi gotten dragged into it too? It was possible he'd be stuck like this forever, because even if he figured out the lesson the metahuman power demanded from them, he doubted his stubborn little brother would ever learn a thing. After all, Yuuto's dear older brother had been trying to teach him common sense for years and always miserably failed.
They might never get their real bodies back.
Hisashi huddled under the bedcovers, coughed, and felt sorry for himself.
The vault door slammed open so fast it bounced off the metal wall. Hisashi's head shot up.
A blond man with spikey hair and squinty red eyes stood in the doorway. He placed his foot on top of one unconscious minion. Another dangled from his grip. Flames danced down his arms.
Only one fool would dare invade All for One's most secure safehouse and go after his most treasured possession. This could only be his pathetic little brother's most idiotic friend, Kaji Bakugo.
"Missed me, you shitty invalid?" Kaji grinned, flashing two fangs. "I'm here to rescue you, Yuuto."
OMAKE TIME!
Omake: From the Vault
Hisashi: I'm sorry now. I never should have put you in here. I completely understand why I was wrong. Let me out.
Yuuto: What, really? No, I won't be fooled so easily! You're just pretending to be sorry!
Hisashi: Why did you pick a moment like this to grow a brain?
#
Omake: Hisashi Versus Author-Chan
Hisashi: I'm going to kill you for this.
Author: With what quirk?
Hisashi: …
Author's Note:
To my knowledge, this is the first fic where All for One gets vaulted by his younger brother, and I am extremely proud of this. Serves him right!
This story uses the same characterizations for All for One and the First as Custody Battle, but completely stands alone. Previous readers, assume this is a different timeline from Custody Battle.
Kaji Bakugo is the Second One for All User and a distant relative of Katsuki Bakugo. Of course, there is no One for All in this story because All for One tried to give his brother a karma quirk instead. Kaji is the one who would have inherited the quirk had the universe gone in a very different direction. (FYI: he has the same personality as the Second in "Four Ways the First One for All User Could Have Died" but a different backstory, since he never worked for All for One.) This is the point where, in canon, the Second would have showed up to rescue the First from the vault…but because of the body-swap, he just rescued All for One instead. Oopsie!
I know Gigantomachia probably wasn't around during the dawn of the age of quirks, and I don't care. I wanted him in my story, so here he is. He's currently much smaller because he hasn't gained his size quirk yet, so he's going by Machia.
Kenjiro Ui is All for One's bodyguard from the flashback in Chapter 193. So needless to say, Yuuto has a reason to hold a grudge against that minion in particular.
Yes, Hisashi currently has Yuuto's ability to pass on his quirk to anyone who ingests his DNA, but he doesn't realize it. If he managed to get rid of the karma quirk so easily, this would be a very short story. He still has all kinds of suffering (cough) valuable moral lessons to learn.
New update schedule for my stories:
Sunday: Karma Quirk
Tuesday evening: A Life Not Lived
Thursday evening: Five Times Darth Omnus Found Out He Had a Son and One Time He Succeeded in Turning Izuku to the Dark Side