Work Text:
As a teenager, Deku had become an expert at keeping secrets. It all started when the Number One Hero approached him one day and offered him his quirk with the words, “You can become a hero.” Heroes were supposed to be transparent, Deku always believed as a child. The smiles on their faces as they saved innocent lives were meant to be genuine, the reassurances they offered drawn from truth.
Moments after being told that he, too, could be a hero, Deku learned that the honesty of heroes was a lie.
At that moment, Deku received the first secret of his hero career, and man what a weighty one at that. The small misleading half-truths he told to hide One For All and All Might’s secret true form took on more and more weight until Deku couldn’t hide it from himself anymore: he was a liar . He had never been a liar, but now, here he was, lying to anyone and everyone. Even his mother. But, anything to protect Toshinori and One For All, right?
As he grew older, after Shigaraki was defeated and Deku could at least hope that the ages-long battle with All For One was over, Deku’s lips grew looser. He didn’t tell the public about One For All of course, but he finally let his mother in on the secret. Then Shouto, because of course he would tell the man he married. Then Aizawa, because the poor man had had to put up with him for so long that he at least deserved to know.
Uraraka and Iida learned because he wasn’t not going to tell his two best friends after telling his teacher; Kirishima learned when he married Bakugou; Tsu learned when victory over a villain necessitated it… Eventually there were more people who knew than didn’t.
But there was one secret he never told.
Because he’d never hear the end of it.
Because he knew it would bring about his death instantly .
But it wasn’t like he had a choice anymore.
It was almost reminiscent of the fight against Shigaraki, directly after he had inherited All For One. Deku, Shouto, and Bakugou alone (they had felt so alone) against a villain they couldn’t hope to beat. This time, there would be no reinforcements. It was just them, the top three heroes in Japan, standing between an overpowered maniac and the town where hundreds of civilians were in an induced sleep. They wouldn’t let her get to them.
Deku had no choice. Shouto was already unconscious. Bakugou was pinned beneath rubble; still fighting to free himself with weak blasts, but Deku knew he was fighting a losing battle, he wouldn’t be able to stand even if he managed to get free. He really had no choice. The villain had already deflected Deku’s various quirks, the ones he had lied through his teeth to pass off as his own. She was too strong. Reminiscent of All For One’s power. Or Nine’s. Deku remembered, through a haze of blood, how powerful Bakugou had been fighting Nine. How the villain had hardly been a match for his powered-up blasts.
It’s not like there were any witnesses, besides one who already knew about One For All, and a villain who (the Number One Hero could find a convenient quirk to make it happen) would conveniently forget about it later.
Deku had no choice but to let his last secret slip.
And the villain exploded in a fiery blast.
***
Looking back, Deku probably should have knocked Bakugou out before using his quirk. That way there would have been no witnesses, and he would not currently be dangling by his shirt collar over a 30-story drop. He looked to his husband for help, but Shouto merely sipped his tea. Neither of them really believed that Bakugou would drop him off the balcony of the hospital room where the two of them had been recovering for the past four days. Bakugou still seemed to be making up his mind.
“This is fucking it ,” Bakugou growled. “You’ve crossed the final fucking line, I’m actually gonna kill you this time.”
“Kacchan—”
“ NO ! It’s time you fucking explain yourself. What the fuck Deku??”
Typical of Kacchan to storm into Deku’s hospital room and make death threats the moment he was able to walk again.
“Maybe— put me down first?”
“Yeah I’ll fucking put you down!” And Bakugou let go.
Deku fell for maybe a foot before activating Shimura’s Float quirk and climbing back into the hospital window. Bakugou scoffed and crossed his arms as Deku sat back down on his hospital bed.
“How the fuck did you get my quirk?”
The question was softer this time; not exactly curious , but not murderous either, which was probably the best Deku could hope for. He knew Bakugou had every right to be angry. Or at least spooked. He knew he would be terrified, if he saw someone else using his quirk, who had no business being able to use it.
“It um— it all started back when we were first years…”
Deku explained it all to him. How Bakugou didn’t remember, but he had temporarily wielded One For All in the battle against Nine. How it had returned to Deku, but not without a trace of Bakugou left behind. He wasn’t sure what One For All considered Kacchan. The nine-point-fifth holder? OFA’s embarrassing one night stand? Whatever it may be, Bakugou had touched One For All; in essence, he became one of the past holders on that day.
Bakugou groaned. He knew what One For All liked to do with the past holders’ quirks.
Deku found out about Explosion around the same time he started using Blackwhip and Float. He didn’t dare tell Bakugou about it, of course, and this secret he even kept from All Might. Toshinori hadn’t suspected a thing; it was unprecedented for a holder of All For One to temporarily pass the quirk on just to get it back. So Deku was allowed to learn to navigate Bakugou’s quirk in solitude. This led to many sleepless nights of practice, and many burns, and many, many cuts and scrapes from attempting to fly, failing miserably, and forgetting he could use Shimura’s quirk too.
But Deku didn’t mind. He’d seen the power that Bakugou’s quirk had had backed by the full power of One For All. He knew he would need it in a fight one day. And what were some cuts, scrapes, and burns compared to the dozens, if not hundreds, of times he had broken his arms and legs over the years?
Bakugou’s scowl deepened as Deku finished his explanation. “You dumbass bastard.”
“Kacchan!??”
“Don’t Izuku,” Shouto said. “He’s too shell-shocked to come up with a better insult. Treat him with care.”
“Shut your face, Half-and-Half bastard,” Kacchan growled.
“I need you to understand that I am the exact opposite of a bastard,” Shouto deadpanned.
Bakugou flipped him off, but otherwise ignored the comment. “Deku is a dumbass, he could have killed himself with that quirk.”
“Rude, my Izuku has almost killed himself with seven different quirks. I guess eight, if you count One For All itself. Mighty bold of you to assume yours would be the one to do him in.”
“Deku has been blessed to get his hands on my quirk and he damn well knows it, right nerd?? You don’t get a chance at this kind of power every day!!”
“You say to the man wielding One For All,” Deku snickered.
“I’ve beat One For All in a fight plenty of times!” Bakugou yelled.
“You beat One For All in a fight once , when I could use, like, 5% of it.”
Shouto realized what was happening too late. He couldn’t stop it.
“Meet me in the courtyard at sunset, fuckface! It’s time for our next rematch!”
Now Shouto was going to have to watch his husband beat Bakugou with his own power. The fight might be fun, but the emotional aftermath would not; everyone knew that Bakugou’s ego was as fragile as a kitten.
***
In the end, the fated duel did not happen at sunset (though Shouto’s idiot boys seemed to think they were in a shounen anime or something). Bakugou was ready to fight. Deku was more than happy to show off the moves he’d copied from watching his rival for years. Shouto even had his camera ready to send a video to everyone who knew about One For All; Toshinori would probably be worried, but Aizawa would get a kick out of it. It was fun watching the two most powerful heroes in Japan catfight when you were no longer in charge of their education and general wellbeing.
But the nurses said no.
Japan’s top three heroes whined like children denied their playtime.
The nurses shooed them back into their rooms like 19th century milkmaids clearing cats from the alley beside their house.
So the three pro heroes were forced to recover in peace without inflicting any more injuries on each other, the poor unfortunate things.
When Deku and Bakugou did meet to fight, it was after they had been discharged from the hospital. Granted, their injuries hadn’t fully healed, but at least now they weren’t the hospital’s responsibility. They met on the beach where Deku first inherited One For All; perhaps he thought the sentimental location would augment his strength.
Bakugou lit small explosions in his palms. Shouto slurped a bowl of soba and readied his camera.
The fight lasted for approximately five minutes, and it was hilarious . That is, it was hilarious for Shouto. And Deku. But probably pretty embarrassing for Bakugou. Deku copied all of Bakugou’s signature moves, laughing all along, overpowered explosions tearing up the beach. He maneuvered through the air as Bakugou had always done; he used his AP Shots; he even managed to crudely copy the Howitzer Impact, though he’d admit later that he had never practiced that one.
And for the final blow — as if Deku was trying to taunt Bakugou (he was) — he let loose his full power with a scream of “DIE!!!” and Bakugou was left coughing and unable to stand on the beach.
Shouto stopped the video and hit send, then lazily jogged over to where Deku was helping Bakugou get shakily to his feet and climb out of a crater of sand rimmed with glass.
“That was pretty decisive,” Shouto pointed out.
Deku laughed. Bakugou scoffed.
“That’s only,” he said, “because One For All’s a little shit.”