CW: Blood & Injury, Canon-Typical Violence, Temporary Character Death

~

Chapter Summary:

Brothers help brothers...
(Oh no. Why would I use that phrase. It only hurts my own feelings D:)
...and the adventure comes to a close.

~

"Deku-" Kacchan started, then bit his tongue and screwed up his face, shoulders squaring and hands plunging into pockets. "Izuku."

"You can call me Deku," Izuku responded automatically, chewing on the end of his pencil before scribbling something down in his notebook as he walked. "It's kinda like dekiru, I like it..."

"Deku," Kacchan began again, his grinding teeth practically audible as he stormed alongside the boy. "Teach me."

"Teach y-?" He lifted his head, blinking in surprise and half-tempted to teasingly ask his friend to clarify, but that would be a bad idea. "To fight, you mean?"

"And all the other shit," he grunted in confirmation, lower jaw jutted out and his crimson gaze glaring forwards.

"You mean like... laws, first-aid, tactics, approachability-"

"Yes," Kacchan snapped forcefully, looking like the action pained him, paces turning into stomps.

"Right- um, okay, uh-" Izuku fumbled to close his notebook, swinging his bag over one shoulder to dump both bits of stationary inside and cast a curious glance sideways. "How about right now? Well, not right now right now, but I mean-"

"Fine."

"Really?" He could only gape for a second, although was quick to shake himself and move forward was a bounce in his step, hands clasped around the straps of his bag. "Great! First, I need to go home, so you can say hi to Tenko-kun if you want - do you have gym clothes to change into? Because we can grab a snack and then go for a run, and in the park we can practise fighting techniques together. How long are you allowed to stay out for? Because we'll be tired after sparring so we could take a break, or do some studying together if you want – oh, we got homework today, we could work on that-"

"What happened, that night?" Kacchan asked, his tone hushed and unexpectedly soft. "You weren't at school for weeks, Deku, then you come back with scars and you're prattling on about having a new brother, as if nothing weird ever happened."

Izuku faltered for a moment, memories of fire and destruction and fear rising in his mind, but a small smile tugged as his lips nonetheless. "You know that big villain fight All Might got in? I was in the area at the time. Um... I found Tenko-kun, and we tried to run away together, but... it was really dangerous, Kacchan. But it turned out okay, anyway, so... Tenko-kun has no living family, so he was going to go into the foster system, but, well, you know what my mum is like. She went through the paperwork and legal issues and she fostered Tenko-kun, which is good, really, because I don't think he'd be as happy or feel as safe anywhere else. So he's kind of my brother now, I guess? It's nice." He paused, side-eyeing his friend who had a frown. "Please be kind to him, Kacchan. He's been through a lot."

Kacchan remained quiet, his narrowed gaze flicking to the other boy before he made a vague grunt of acknowledgement. Izuku opened his mouth but shut it again, not knowing what else to say. The two of them walked the rest of the way home in a sort-of-comfortable-but-not-really silence, both of them deep in thought. Inko opened the door and brightened considerably when she saw the blond, who snarled in protest as he was drawn into a soft hug but didn't make any moves to pull away.

"It's good to see you again, Katsuki-kun!" She beamed, ushering the two of them inside. "Tenko-kun's in the living room, playing that new game Yagi-san bought. I'll make you some snacks, make yourself at home!"

Izuku carefully toed off his shoes while Kacchan kicked his off, both of them practically racing to the living room, falling back into old routines of sitting on the floor in front of the sofa to stare at the TV. Tenko barely spared them a glance, sitting cross-legged on the sofa, hunched over the controller as he aggressively pressed the buttons, no fears of disintegration thanks to the light blue gloves. Kacchan occasionally shot him wary, curious looks, but eventually got too into the gameplay and started to yell commands that could be considered very aggressive advice.

"So you're Kacchan," Tenko suddenly spoke up, his gaze not moving from the screen.

The mentioned boy stiffened uncomfortably, mouth slowly closing as he fell silent.

"From what I've heard, I don't really like you that much," he continued in a nonchalant tone, clicking buttons punctuating his words. "You've never been very nice to Deku-kun, have you?"

"What-"

"He talks about you like you're incredible, but I think you're just a little brat, pushing everyone around just because you have a powerful Quirk? That's not nice. Don't you want to be a hero, Kacchan?" Tenko's voice grew scathing and taunting, growing uncomfortably close to sounding like Shigaraki.

"Shut-"

"Tenko-kun," Izuku began, clenched hands pressed against his thighs, "please don't... do that. Kacchan... has made mistakes. A lot of them. But a lot of his personality has been bred from the foolishness of adults who should know better."

Kacchan blinked, teeth bared in confusion. "What."

"People always praised you, and no-one ever went against you or fixed your mistakes, so you never realised what you were doing was wrong." Izuku shrugged, shifting his position and pulling his legs up to his chest to rest his head on his knees. "It's not your fault, not really. But you finally came to me because you realised you could be better, right?"

"What kind of useless hero doesn't know how to fight, huh?" Kacchan shot back rhetorically, crossing his arms churlishly and slumping back against the sofa cushions.

"I'm glad you came to me, Kacchan," he said softly, hiding his fond smile behind the arms wrapped around his legs. "We're going to be the best heroes. Together."

*

It was difficult to keep himself from grinning, but since his cheeks were already hurting he was trying to stop it. Izuku bustled around his room, double-checking his appearance and the contents of his classic yellow backpack before swinging it over his shoulder and dashing out. His mother engulfed him in a hug and Tenko looked up from his phone, flashing a crooked grin and unhooking something from the pocket of his dark trousers. Izuku pulled away from Inko and squinted warily at the older boy, but Tenko just grinned wider, reaching out and smoothing something over his head, letting the ends settle just behind his ears.

"An All Might headband," he informed, snickering as the boy almost immediately teared up, letting out a surprised noise as Izuku threw himself forwards and pulled him into a tight hug. "Oh, come on, it's not that big of a deal."

"T-thank you, Tenko-nii," Izuku mumbled thickly, squeezing a little before backing up and wiping his eyes.

"Yeah, yeah, I'm the best big brother," he muttered bemusedly, ruffling green curls and turning towards the door. "Now hurry up, we've gotta go or we'll be late to school."

They waved goodbye to their mother, who was sobbing uncontrollably but beaming nonetheless, and left their home. Toshinori had wanted to walk them to school, but thankfully had been persuaded out of it, because the last thing Izuku needed was people making a big deal out of him arriving with All Might himself. Kacchan met them at the train station, flashing a cocky grin and lightly shoulder-checking Izuku before they all boarded, standing alongside one another and gleaning dumb stories about Tenko and his classmates to ease their nerves.

UA loomed before them, windows glinting in the sun. Tenko spotted his friends and lightly ruffled Izuku's hair, then caught Kacchan in a headlock to give him a noogie, before the older boy dashed off with explosions in his wake, cackling almost maniacally. A low growl rumbled in Kacchan's throat but he let his arm drop, aggressively tussling his spiky hair back into style and continuing to stomp towards the front doors. Izuku bounded after him, eventually taking the lead as he guided them down familiar corridors, sweet nostalgia bringing a wide grin to his face.

"That's a creepy smile, Deku," his childhood friend muttered, lightly shoving him into a wall.

"I'm happy to be back here, Kacchan, let me smile creepily!" Izuku retorted, pushing the other boy with a shoulder and glaring.

"If you try that again, I'm going to blast you out that window," Kacchan warned, raised palm sparking. "But I don't want to be late on the first day."

Izuku suddenly came to a halt, one corridor away from their classroom. The volatile boy paused a few paces ahead, glancing back with a glower, although his expression was tinged with an unspoken question.

"Oh," he mumbled, green eyes widening with realisation and a giggle spilling from his mouth. "I befriended all our classmates, but I never introduced them to one another."

Kacchan's mouth fell open and he rolled his eyes aggressively, hands thrown out in disbelief. "Are you fucking serious."

"So they all know me..." He trailed off, slapping a hand over his mouth and turning around to try and hide his chuckling.

"But they don't know everyone else also knows you," Kacchan finished, a huff of laughter hissing through his teeth. "Okay, fuck being late, I don't give a shit about that anymore. This is a once in a lifetime opportunity. I need to see their reactions. God, Deku, thank you for being a moron."

"You're welcome, I think?"

The two of them leant against a wall, getting odd looks from the other students who were walking by, but luckily none of the people were their classmates. Izuku entertained himself by flipping through his latest hero analysis notebook that was almost entirely encoded, just in case it fell into the wrong hands. Kacchan jabbed a finger at one of the characters, pointing out a mistake, then returned to silently reading it over his friend's shoulder. Finally, the warning bell rung and they shared a mischievous glance before approaching their classroom, staring up at the intimidating door.

A rustle came from the floor.

"Morning, sensei," Izuku greeted without even looking down.

"Aizawa-sensei," Kacchan acknowledged, too busy getting out his phone and switching onto camera mode.

There was a soft, world-weary sigh. "I don't think I want to know how you managed to figure out I was going to be teaching you. What I do want to know is what the two of you are doing."

"Filming the result of an unintentional prank," Izuku responded, adjusting his tie and composing himself before giving a thumbs-up at the camera. "Ready, Kacchan?"

"Ready."

Izuku reached out and pushed the door aside, a sunny smile on his lips as if he was oblivious to the chaos and confusion that was undoubtedly about to ensue. Aoyama Yuuga noticed him first, perking up and sparkling excitedly. He chirped out an effervescent 'bonjour' that alerted the other students to the new arrival, causing several heads to turn and a wave of visible joy to sweep across the classroom as each individual recognised their friend. Tokoyami Fumikage gave him a slight nod while Kouda Kouji offered a shy little wave. Satou Rikidou straightened up and Ojirou Mashirao's tail started to wag a little. One of Jirou Kyoka's earphone jacks raised in a lazy flick of acknowledgement.

"Yo, Midori!" Kirishima Eijirou exclaimed, half-tumbling off the desk he was sitting on in his eagerness to approach.

"Why didn't you tell us you got into UA?!" Ashido Mina added in a shriek, bumbling after and immediately latching onto the freckled boy.

"Oh, you know Deku-kun, too?" Uraraka Ochako inquired, her tone surprised and her eyebrows raised.

"'Zuku! Thanks for helping me study – there was no way I'd have gotten in without your help," Kaminari Denki said with a cheerful laugh, leaning back in his chair and kicking his feet onto his desk.

Izuku beamed back, happy to know his tutoring helped. "It's no prob-"

"Yeah, thanks for sparring with me!" Hagakura Tooru chipped in, her sleeves waving in the air. "I'm super strong now, so I passed easily!"

"You sure seem to know a lot of people, Izuku-chan," Asui Tsuyu commented, head tilted a little to the side and large eyes questioning.

"Yeah, dude, it's almost as if you know everyone in this class!" Sero Hanta joked, glancing around the room with a sharp smile that faltered as he registered the familiarity with which everyone regarded the boy. "Wait... seriously? Does everyone know Izuku? No way..."

Shouji Mezou gave a sheepish sort of shrug. Yaoyorozu Momo nodded daintily, seeming as bewildered as everyone else. Todoroki Shouto's lips quirked into a faint smile. Shinsou Hitoshi raised an eyebrow, surveying the class. Iida Tenya made a noise of affirmation, while everyone else offered their own confused agreements, squinting around at each other and looking perplexedly back at Izuku.

Aizawa took that moment to finally intervene, shedding his sleeping bag as he stepped inside with an exhausted expression. "Settle down. I'm your homeroom teacher, Aizawa Shouta-"

"Hey, isn't that the underground hero, Eraserhead?" Monoma Neito muttered, and the seated students erupted into excited whispers, because how could Izuku resist sprinkling in his admiration for their secretive teacher when he chatted with his friends over the years?

The inevitable hero-worship that the man despised was just a bonus of introducing them all to one of the greatest heroes ever.

Kacchan made his presence known with a snort that morphed into a snicker, stopping the recording and shoving his phone back into his bag to keep the blackmail material safe. He strode across the classroom, smacking Izuku's raised palm in a high-five before dropping down into his seat in front, lounging back with one arm leaning over the backrest. His feral grin didn't falter under the disapproving glare from their teacher. Sensing defeat, Aizawa turned his terrifying glower onto the plain boy, clearly working out that the strange child with impossible prediction powers likely had something to do with the entire class nerding out over an obscure hero. Izuku clasped his hands together on his desk and he tilted his head with an innocent smile, gaining a faintly frustrated huff before the teacher regained control of the classroom with a glint of his red eyes.

As nice as a second attempt at life seemed, it was difficult to get used to the unexpected restart.

But, hey – helping his friends and stopping awful villains before they even emerged certainly made things worth it.

~

Does Izuku get One for All?? Who knows!! I do like the idea of Izu becoming the first Quirkless Pro Hero (because we all know he'd easily achieve that), but I also don't like imagining anyone else getting OfA,,, it's Izuku's Quirk, not theirs! hehehe

Do Katsuki and Tenko know about the time travel thing?? idk probably, I'd imagine Izuku wouldn't keep it from family, and he'd eventually tell the others in class as well

I know, I know, Tenko's older than UA-age in canon, but I really wanted big-bro Tenko to welcome the two bastard boys to UA, bc that would be cute as hell 🥺 And imagine all the shenanigans they can get up to..... ohhh so good.

I never know how to end fics so this ending feels kinda shoddy but ehh nevermind. Hope you enjoyed the story! It's a huge relief to finally have it all posted after leaving it, completed, in my drafts for over a year by accident, haha oops-
This was kind of a departure from what I usually focus on in stories, because most of the time I slog through slow bonding scenes just to get to the exciting action scenes quicker - whereas here there was a lot more focus on the relationships! idk if it was any good but it was worth it for the practise (: