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i.
Izuku doesn’t have very many soft memories of his childhood with Kacchan.
Being Kacchan’s friend meant lots of running through thick underbrush in the pursuit of stray cats and beetles, wrestling in the sandbox, endless competitions (who can swing the highest? Who can eat the fastest? Who can hold their breath the longest?), races to the convenience store to buy the latest All Might comic/collector cards/dime store figurine, and run ins with intimidating older kids. There’d barely been a moment to catch his breath, but that’s what had been so fun about being friends with Kacchan. He was quick enough to come up with adventures, charismatic enough to lead a group of scrappy neighborhood kids (and get them to include Izuku with minimal protest), and energetic enough to just keep going . Kacchan had always been remarkably present , even as a child. There was nothing distracted about him - when he was focused on something, whether it was an expedition through the park or homework or the newest All Might film, he gave it everything he had to offer, whether it was excitement or frustration or triumph. Kacchan’s victories had always been addicting to Izuku, even if they were at the cost of his own happiness (which was where fissures had perhaps begun to lightning through the mould of their bond).
There was one memory, though. Something that snuck up on Izuku years later when he was least expecting it, along with a phantom warmth that left a dismal ache in his chest when the feeling finally passed.
A particularly bad storm had struck the district when Izuku and Kacchan were eleven years old.. Rain water flooded the streets and thunder shook the sky and the students were stranded at the school for a night. For Izuku, who was quirkless, didn’t have any friends, had only just grown out of wetting the bed, and was still fiercely dependant on his mother, it had been an absolute nightmare. While the other students were giddy with the excitement of an impromptu sleepover and the teacher’s were too weary to calm the flurry of action, Izuku had huddled in a corner with his head between his knees and struggled to stay calm.
He stayed that way, freezing with panic, paralyzed and ignored, until something warm and soft and smelling faintly of burnt toast had been dropped on him.
Startled, he’d looked up around the hoodie draped on his head to see Kacchan standing over him, scowling but - mercifully - not yelling at him. Izuku didn’t think his shaking rabbit heart could have taken berration from Kacchan in that moment.
Instead, Kacchan snorted and said, “It’s time to go to bed, stupid Deku. Come on, already.”
Izuku had grabbed his backpack and followed Kacchan on instinct, to where he’d rolled out two mats side by side. The other kids had quieted, some of them watching openly as Kacchan took Izuku’s backpack and tossed it carelessly next to his.
“We’ll use them as pillows,” he declared. Then, noticing the attention they were drawing, Kacchan snarled viciously, “What the fuck do you losers want?”
The rest of their class ducked their heads and returned to their friends after that. They gave Izuku and Kacchan a noticeably wide berth, but Izuku, drowning in the warm hoodie, had been to caught up in his panic to care about anything else but the strange kindness Kacchan was showing him.
Moving robotically, Izuku had lain down on the matt next to Kacchan and curled in on himself.
Lying on his side, watching him with twisting garnet eyes, Kacchan had said, quietly this time, “You’re fucking shivering, Deku. It’s not even that cold.”
“S-s-sorry, K-kacchan,” Deku stuttered around lips that were, in fact, shivering.
Sighing impatiently through his nose, Kacchan had yanked his matt closer and, moving like he suddenly wasn’t quite sure of himself (which was startling enough), tossed an arm rigidly around Izuku’s thin shoulders.
Izuku, a soft summer child still used to cuddles with his mother, had known instinctively what to do before a fresh panic could overtake him.
He quickly burrowed into the inviting crevice between Kacchan’s jaw and shoulder. Kacchan hissed when he pressed his cold nose to skin exposed by the loose collar of his faded All Might t-shirt, but when Izuku tried to pull back to apologize, Kacchan’s arm only tightened stubbornly.
Izuku relaxed after a heartbeat.
His breathing had steadied, when he matched it to Kacchan’s. The heat emanating from Kacchan’s body was complete and smothering, and Izuku had wondered vaguely if he simply ran hot because of all the fire in his veins begging to be set loose. As the shivers melted from his bones, Izuku tangled their scrawny legs together, and finally closed his burning eyes.
He finally felt safe enough to do so.
“Just don’t piss yourself in your sleep, alright? That’d be fucking disgusting,” Kacchan muttered.
“I w-w-wouldn’t!” Izuku squawked around the stupidly happy smile on his face, hidden against Kacchan’s shoulder.
After a long moment, Kacchan buried his face into Izuku’s curls and sighed out the last remnants of tension holding him hostage. The arm around Izuku held him close enough that every inhale brought with it the smell of burnt toast and cinnamon - smells that Izuku would forever associate with Kacchan years and years later.
Curled tightly together, with the sounds of their classmates whispering and a storm thrashing wildly outside, they had both fallen into deep, deep sleep.
When Izuku had woken up, warm with the fading imprint of Kacchan’s body, he had been alone.
After that, the quirkless insult started to get thrown around with more velocity than before, and it guaranteed that Izuku stayed alone until his enrollment at UA.
ii.
Two years of training at UA hadn’t left much room for the resentments Izuku and Katsuki had screamed at one another in their first year. While Izuku was still twitchy whenever Katsuki spoke to him and Katsuki had to make a conscious effort to not yell when Izuku’s muttering grated on his last, tightly strung nerve, after two years of beating the snot out of one another without reservation, they had also beaten and moulded and reforged their relationship into something that almost could be called friendship, or camaraderie at the very least.
But there was still something Izuku couldn’t quite place his finger on, some unspeakable feeling that made the air between them taunt enough to make Izuku’s skin spark with barely contained energy and Katsuki’s eyes roil like blood red thunder clouds whenever they were within orbit of one another, but whether it was lingering hostility or just plain old competitive spirit, Izuku could never tell without feeling like he was missing the mark entirely.
“Maybe it’s sexual tension,” Ochako said cheerfully next to him.
Izuku dropped the plate he’d been washing.
“W-w-wha - pardon ?” he whisper-shrieked, glancing frantically over his shoulder to where the rest of their class were roughhousing in the dining area. His gaze immediately caught and held onto where Katsuki was squished between Kaminari and Sero. The blonde was laughing, actually laughing - that harsh, rasping bark that had gradually become as familiar around the dorms as Aoyama’s flamboyance and Kaminari’s school-related panic - at something Jirou had said, and Izuku felt abruptly faint. The hard line of Katsuki’s tanned jaw. The pieces of honey that the sun had brought out in his white blonde hair. The sharp roll of his broad shoulders. The stretch of his signature black tank top.
He spun back around before Katsuki could sense his stare, like he had a habit of doing.
Ochako was grinning, brown eyes sparkling. Izuku realized with no small amount of dread that something about his reaction had satisfied her.
Blushing furiously, he turned back to the task at hand. “I don’t know what you’re talking about, seriously. That’s …. I mean, that , with - with Kacchan? I mean. That’s, ha, that’s absurd .”
She shrugged amicably. “Just thought I’d throw it out there.”
“And you’re gonna let it go?” Izuku asked, suspicious. He knew his best friend better than to think that she would ever just let something go without getting a satisfactory answer. He gulped. Maybe his reaction had been all the answer she needed.
Her smirk told him he was on the right track.
Between finishing the dishes and completing his nightly exercises, Izuku was one of the last to slump tiredly into the room commandeered by the boys for the duration of Aizawa’s Summer Training Camp From Hell (so far it had lived up to its name).
Shivering faintly after moving from hot springs to the air conditioned halls, Izuku blearily picked out an empty futon and fell onto it with a shameless groan. His muscles felt spongy and useless, and he immediately melted onto the mattress, only prying his eyes open when he felt a whoosh of air against his face and heard the muffled thump of a body falling onto the futon beside his.
Burning red eyes stared back at him, unabashed. Katsuki was watching him, not saying anything.
God, did the boy ever blink ?
Maybe it’s sexual tension?
Izuku stiffened. He was so tired he could hardly form a proper greeting, but the silence, taunt and rippling with something , was killing him .
Katsuki ruffled his damp curls and said gruffly, “I can hear you thinking, nerd. Shut the fuck up and go to sleep.”
Izuku barely had time to savour the faint scratch of nails against his scalp before Katsuki pulled away, and he was all at once acutely thankful for his exhaustion, because everything in him wanted to lean into Katsuki’s touch. Let it last a little longer. Let himself indulge in whatever Katsuki would offer.
“Do you ‘member that time when we were storm stayed at school?” Izuku heard himself slur, voice mostly drowned out by the chatter of the others.
Katsuki’s sharp glance told Izuku that he had perfectly fine. Arms folded behind his head and staring carefully at the ceiling, Katsuki said, “Yeah.”
“Mmm.”
“God, you were so fuckin small. Shivering like a goddamn leaf even though we were inside.”
Izuku glared half-heartedly. “I was scared .”
“Of what? We were perfectly fuckin safe. Unless …” Katsuki’s faint grin sharpened. He was looking at Izuku again, garnet red eyes bright and playful and utterly intoxicating, “unless you were scared you were gonna piss yourself in front of everyone.”
“Oh my god. ”
“Since we’re taking a trip down memory fucking lane, how about that sleepover we had when you -”
“Shut up. You’re the worst , Kacchan,” Izuku wailed, covering his ears.
Katsuki was positively cackling now. “It took you so long to grow out of that.”
“It took me a perfectly normal amount of time, thank you!”
“Dude, you were eleven .”
“Yeah, and it was normal .”
“What are you guys talking about?” Kirishima called jovially from the other side of the room.
Exhaustion forgotten, Izuku shot up and slapped a hand over Katsuki’s mouth. “N-nothing!” he chirruped.
Kirishima shot him a toothy grin and thumbs up ( what for? ) and turned back to arm wrestling Dark Shadow.
Glaring back down at Katsuki, Izuku very quickly became aware of the laughter that was vibrating up his arm.
The lips that were pressed against Izuku’s hand holy god in heaven .
Izuku was caught for a moment - caught in the dance of light in Katsuki’s eyes ( had they always been flecked with that lighter shade, what was that, was that amber? ) and the summer freckles dusting over the bridge of Katsuki’s crooked nose ( I want to count them I want to count them I want to count - kiss - them ).
When he realized that Katsuki was no longer laughing, but instead staring back with a steadiness that he hadn’t possessed a shred of in their first year - not quite patience but more an animal wait - Izuku forced himself to pull away, heat shimmering under his skin.
Flopping back onto his side, Katsuki rolled so that they were facing one another. They were both breathing a little harder than they had been before.
“That was a long time ago,” Katsuki said. His voice was rough, and rasped over Izuku in a way that made his toes curl.
“It was,” Izuku agreed, because truly, it was. Lifetimes ago, even.
Embarrassment aside, that brief shot of adrenaline had drained out of his body and he was once again melting into the futon. Sleepiness guiding him, he fumbled with his next words. “I always wanted to, um … thank you, for that. You know.”
“For what?” Katsuki rumbled softly.
Izuku smiled. He forced his eyes open. Seeing me. Keeping me warm.
“Never mind.”
Katsuki scoffed.
Like some sort of permission had been given, Katsuki shifted ever so slightly closer, and brought his warmth with him. This time, when he reached out - and Izuku was reminded of that same arm being tossed across his person and holding him tight against a bony chest - he buried his hand in Izuku’s curls, and he wasn’t so quick to pull away. Tentative fingers dragged against Izuku’s scalp and tugged gently through knots, traced the shell of his ear as Katsuki grew more confident and Izuku didn’t pull away, twisted strands together only to watch them unravel and spring back into place.
Izuku squeezed his eyes shut, because he couldn’t stand to look Katsuki in the eye anymore ( too vulnerable, too full of old hurts and aches ), and he would rather have them closed than look anywhere else. His heart was beating a war drum in his chest, he could feel the pulse of it through his entire body, and the tell tale burn of tears was building in his throat. He stayed very still and refused to let himself cry, as though Katsuki was something wild that had spontaneously approached him, and savoured every touch until he couldn’t fight the black tide pulling him under.
He wakes up to muffled giggles and whispers and the click of someone’s camera phone going off. Unconcerned, Izuku buries back into the hard line of warmth pressed up against him and doesn’t give it a second thought until Katsuki is waking up and disentangling himself from Izuku’s clingy octopus limbs, bright red and muttering apologies.
iii.
Izuku has many soft memories of Katsuki, and his personal favorites go like this.
“Hey. It’s time to wake up. Kacchan. Kaaaacchan.”
“Gnnnnnf.”
Izuku laughs up into sleepy red eyes, softened by the lingering of a good sleep.
“The fuck you laughing at nerd?” Katsuki scrubs his hands through Izuku’s curls and rolls them so his entire body weight is crushing Izuku into the mattress. Izuku gasps and shifts until he can breathe comfortably, nuzzling happily into the junction between Katsuki’s neck and shoulder and breathing in until all he can smell is Katsuki , all he can feel is the hard lines of Katsuki’s body melting into the hard lines of his, the sound of Katsuki grumbling and huffing and nuzzling back just as enthusiastically.
Being Katsuki’s boyfriend means lots of cuddling, particularly when both of them are reluctant to leave their nest of blankets and pillows. It means delicious home cooked meals when Izuku drags his ass home after a sixteen hour shift, the smell of burnt toast clinging to stolen and coveted hoodies, the blending of their friend groups that coalesces into at least three of them passed out on Izuku and Katsuki’s carpet every weekend and a lot of playful matchmaking. It means joining their All Might merch into a force that staggers the man they both fiercely admire, endless binge watching of old footage, the TV series and holiday specials, debating fan theories like the fucking nerds they are, and hunting down rare cards and comics by grossly exploiting their contacts and status. It means family suppers, including, of course, Yagi Toshinori and the odd time Aizawa-sensei and Mic, affairs that are chaotic at the best of times and always bursting at the seams with the love of their parents, adoptive and otherwise.
It means that the air between them shifts from easy and playful to hot and urgent at a breakneck speed after all these years, kisses that move from blinding to heady to bruising to chaste, i love you’s stamped permanently to the inside of Izuku’s thighs, the small of his back, the palms of his scarred hands. It means being on the receiving end of all that prodigal focus when they christen the kitchen counter for the thirty seventh time because thank fuck you’re okay thank god what would I do without you fuck Izuku . It means weathering Katsuki’s storms, yes, but also means being there to watch the clouds untangle and the light shine through. It means that the yelling turns into arms wrapped around him, arms that don’t let go until Katsuki has assured himself that Izuku is safe, Izuku is not going anywhere, and Izuku love love loves -
Katsuki nips his nose. “You’re thinking too loud for,” he reaches over to lift up their abused alarm clock and groans, “ six thirty in the fucking morning .”
Izuku hums. Combs his fingers through tufts of coarse blonde hair.
Katsuki folds his arms over Izuku’s chest and rests his chin, arches a brow. Settles in. They have a few minutes, after all. “Okay. What’re you thinking about, nerd?”
“You,” Izuku says immediately. “How much I love you. How happy you make me every single day.”
Katsuki’s rises onto his forearms, eyes widening briefly, before they slide back into a suggestive slant that matches the curl at his lips. He noses at Izuku’s cheek. “Christ. You’re such a fucking sap .”
Izuku twists his hands behind Katsuki’s neck and tugs him until their lips are a hairsbreadth apart, breathing against one another, and he feels that same rippling thrill that begins in his stomach and lights up every inch of his body, that same undefeatable urge to smile .
“Deal with it, Kacchan,” he says solemnly, mouth quivering. “Because I’m never going to stop.”
Katsuki rolls his eyes, but he can’t disguise his smile either. “Fuck, I guess I-”
Izuku cuts him off with a kiss because he can’t bear it any longer, he just can’t, and Katsuki has always indulged him - whether he’s been aware of it or not.
It means this.
Even when they're apart, they no longer wake up alone.