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1.
It was in the warm, slow, slumbering moments when Izuku began to notice.
Ash blonde hair catching in a glint of light. The scrunch of a nose. Noises he didn't think Kacchan knew how to make, mumbled into the crux of his neck, for him and him alone.
They'd always been vulnerable around each other, in their own twisted, toxic ways. As the years wove their way through their growing limbs, stretching each of them closer until they intertwined, they realized they were the only ones who truly understood each other. And with that intimacy came a new language formed. Feelings hurled at one another like weapons, only to be caught and coddled by the other, cherished and known. Unspoken to anyone else.
Izuku didn't know how long they'd been together at this point. Labels didn't seem to matter to either of them; they just did what felt natural, what was right. They were both logical people, acting on instinct after thoroughly analyzing each possible outcome. It made sense that one evening, after another screaming match that left Izuku's throat hoarse, that they fell into one another to help pick up the pieces they'd stripped down.
They were heroes, after all. That's what they did.
Saved people.
Saved each other.
Sparring matches increasingly ended in open-mouthed kisses, with Katsuki unwilling to let Izuku fully get a handle on his breath again before stealing it completely, greedy, refusing to give it back. Izuku didn't care, though. It seemed to make Kacchan happy, if that dazed look when one of them pulled away had anything to say about it. And Izuku liked seeing Kacchan happy. Liked being the reason Kacchan was happy.
They didn't talk about it. They didn't need to. Everything else in the world was going to shit, and so long as Izuku could feel Katsuki's volatile, steady, realiable presence near him, all was well in his world.
The shift had been gradual, growing from kisses to explorative touches to nights spent in one another's rooms (usually Kacchan's, because if it was one thing they did talk about, it was how creepy it was making out under the watchful eyes of a thousand different All Mights staring down at them). They spoke in the way careful hands traced over scars, followed by a delicate press of lips, an acknowledgement or an apology or a promise all in one.
They didn't need to make each other promises out loud. After all, they'd already made the most important one in their lives: to chase each other until the end of time, for the rest of their lives, beyond the concept of forever. To follow both of their dreams, together.
What could hold more importance in either of their hearts than that?
So, no. Katsuki and Izuku weren't boyfriends.
It was something much more than that.
But Izuku didn't mind not being able to name it. He always stammered out his words, anyways, and Kacchan much preferred action over speaking.
Doubts enjoyed making a home in the caverns of Izuku's bustling mind. But none could be found, or rather all were chased away in the way Kacchan's arms encircled him, tugged him in close, held him against his beating heart.
They were curled up on his bed on a rare afternoon free of study sessions or extra sparring lessons. Perhaps it was the fact that they had (somehow) made it to their third year at UA, or more likely the fact that they'd fought to end a war that they hadn't begun when they were still learning just the start of what it took to be a pro hero. Whatever it was, Izuku thought he could get used to it. Kacchan was slumbering, features utterly relaxed. A sight he didn't see often enough, and vowed to coax out of him more.
The only sign of time passing was the way the shadows along Kacchan's spikes shifted, though Izuku could barely tell even then. He was staring at him outright, lulled into complete peace listening to the steady breath of his best friend boyfriend lover forever.
Of course, he wasn't just staring because he wanted to.
Because he could.
(Because he loved Kacchan.)
No, there was much more purpose to the way Izuku was studying him now. Propped up against the headboard, notebook open on his knee and scribbling observations down every so often. These were the moments, too few and far between, where Izuku could conduct his latest obsession. His newest study, perhaps the most adorable thing he'd ever seen.
Kacchan heaved a content sigh, lips smacking lightly in his sleep. Every time he did so, his fingers twitched, ever so slightly, kneading against the soft comforter as though he was shaping the smallest of ruffles into something more comfortable. But Izuku was watching for every movement, every moment of stillness, and the soft breaths in between it all. Marked each one down pointedly in his dedicated notebook that was quickly filling up.
Because in these quiet moments, he saw it. Whether the other boy wanted him to or not.
Kacchan was a cat.
Not literally, of course. But in every other sense of the word. Izuku was quick and careful to slap his notebook closed at the telltale stir signaling Kacchan was awake, adamant about not letting the other boy see his conclusions lest he risk his inevitable wrath. But Kacchan's breaths were still too deep, so Izuku let his pencil scribble away as he watched.
It was the cutest thing. Normally, they weren't back in the dorms this early. Or, if they were out of classes, Katsuki would drag Izuku away to Gym Gamma to do some extra sparring. But it was nearing the end of the school year, and the air felt full of hope and possibility, and Katsuki had said nothing as he grabbed Izuku by the wrist and tugged him to his room alone. Izuku had stammered and blushed, unready for their activities usually reserved for the dark cover of night. But he immediately melted when Kacchan glanced around his room, eyed the way the late afternoon sun's rays cast a golden glow along his bed. And without another word, he curled up right there on the end of the mattress, forgoing any of his plush pillows, ignoring his perfectly tucked in blanket to instead bask in the natural warmth.
Just curled himself up, head resting on clasped hands as though they were little paws. Eyes closed, unbothered by Izuku or his amused lingering by the door.
Carefully, Izuku padded across the room. Shucked off his backpack, grabbing for his notebook and pencil, then settled against the headboard. Got himself comfy, ready to spend his next few hours (days, years, lifetimes) watching Kacchan.
Izuku was the chaotic sleeper. The one whose legs tangled up in the blankets, leaving Katsuki a fuming mess of curses as he frantically straightened out the sheets and blankets, muttering things like damn nerd, how they hell do you get any sleep if you're just tossin' like this all night. Kacchan slept like a rock. No, like an ancient, slumbering mountain that had gone centuries undisturbed. That perpetual crease between his brows smoothed out, and his jaw unclenched. Fingers, usually so strained, prepared for an explosion at a moment's notice, flattened out. Draped against the soft blanket, finally at rest.
Needless to say, it took a while before the first movement came. Anyone else would've missed it, but Izuku had long ago accepted that he crossed well beyond the territory that was considered normal for how he watched Kacchan.
Just the small scrunch of his nose, like a phantom feather brushed against the tip of it. Izuku stifled a giggle, marked some words down in his notes.
Later, it was more noticeable. Their friends were a muffled roar from the lower levels, cheerful laughter knocking at the door before weaving around in a peaceful comfort, letting Izuku know he was home, safe. But the sound must've roused Katsuki, just a little bit. But it was enough, and he yawned, stretched, eyes still closed, refusing to let sleep slip from his grasp. His arms, so muscular and bigger than they'd been in their first year, reached overhead. Fingers outstretched, palms to the sky, and Izuku just wanted to worship him. Bury his face in his chest, whichever came first. He'd get to the other one eventually, anyways.
Like everything Kacchan did, the yawn was large and dramatic. Sharp canines glinted in the sunlight, a small noise escaping from the back of his throat. Something quiet and girlish, one that a conscious Katsuki would scowl upon hearing.
Once thoroughly stretched and satisfied, Katsuki brought his arms back under his head. Curled up again, and if he had a tail, Izuku had a feeling it'd come up to cover his nose protectively.
"'Zuku?" that tired voice groaned. Eyes still closed, but a hand reached out, pawed along the blankets until they reached Izuku's ankle.
"Yes, Kacchan?"
"Mm," he mumbled, tugging. Izuku chuckled.
"Okay, Kacchan. I'll come cuddle you."
And with that, he carefully closed his notebook, tucked it back away into his backpack, and wrapped himself around Kacchan's front. Forehead to forehead, nose to nose, making sure every bit of Kacchan felt warm.
2.
Katsuki had never been one for physical touch.
The only exception was sparring, where he'd get this crazed look of triumph and glee in his eyes when he'd pin down an opponent, or press a forearm to a chest, feet trampling wrists to keep them down.
Anything else, whether it be high fives, hugs, or a casual arm slung over his shoulder, was strictly forbidden. The more intimate, the less welcome, and the greater eruption you'd get out of the boy.
Few were brave enough to try to walk this boundary. Only in distracted moments, when Katsuki was too focused on what some idiot across the room was saying (Sparky, it was always fucking Sparky according to Kacchan), or when he was zoned out with a dazed look on his face watching Izuku (because he watched Izuku too, it was still unbelievable, but there it was - and Izuku knew this because he, too, watched Kacchan) that someone - usually Kirishima or Ashido - would stroll up and tug him in close under their arm. It would only last a second or two, before Katsuki would return to his senses, hurl them off of him with a grumble of curses under his breath.
Even the teachers knew better than to come too close. All Might was barely deemed worthy, if the grating look on Kacchan's face when his favorite mentor placed a calming hand on his shoulder said anything.
Izuku, on the other hand, was touchy.
Where words failed him, as much as he tried and tried and tried to find the right ones and still came up short, he supplemented his thoughts with touch. Whether it was the air surrounding him when emphasizing a point in conversation, or shaking Ururaka by the shoulders when he had to fill her in on the latest hero news, all of it was part of his language. His way of showing affection to those he felt close to.
Which brings him to Kacchan.
It took a while for the spiky boy to get used to Izuku's cravings. But soon after that first clash of a kiss, Izuku found that more exceptions were being made for him and him alone.
He liked that.
That was the subject of another Kacchan notebook - the one on the general progression of their relationship, or whatever it is they wanted to call it (not important, not in the slightest, because cataloguing things like the way Katsuki's breath caught like that when Izuku brushed fingers along his arm was much more interesting). Naturally, this was another subject of Izuku's tests. Not the 'Katsuki is the secret embodiment of a feral house cat' (full diagnosis still pending), but the 'how far can Izuku go with his newfound Kacchan privileges.'
Of course, there was some overlap of the two, as Izuku was quickly discovering.
A soft grazing of fingertips while Kacchan was cooking, barely there, but enough to make his blonde hair rise on end. Not enough to cause him to bark at Izuku, tell him to fuck off (though, the latter was becoming increasingly rare, or was paired with a sly smirk no one else got to see).
From there, Izuku would hook his chin on Kacchan's shoulder. Whether he was cooking, doing homework, or just watching TV, Izuku would approach cautiously, careful to ensure his footsteps made noise. Not that he'd ever startle Katsuki - even if he tried to sneak up on him, Kacchan always knew where he was. Inch by inch, he'd come closer, until his cheek was a breath away from Kacchan's, chest against his solid back. At first, the boy froze, scowled, looked away with a quick blush. But Izuku was patient, always patient for Kacchan. And before long, he had him sinking into the feeling, and even better, the touches were returned. Izuku would hook his chin on his shoulder, and Kacchan would respond by reaching back to wrap scarred arms around his waist, not an inch left between the two of them.
Hand holding was still rare, but Izuku expected that. He didn't initiate that one, content enough to bump shoulders with Kacchan as they walked to class together. But still, there were some extra special moments that made Izuku's heart flutter, when they'd be walking back from a late night workout, no one but the stars to witness the way Kacchan would lean over, tangle their fingers together. Hands so soft, Izuku felt lucky he got the chance to touch him at all. His knuckles tingled from where Kacchan would brush his thumb over them.
(He'd long since memorized the shape of Izuku's scars.)
Kisses turned to cuddles. Cuddles turned to shedding clothes and discovering just how good all the physical touch could feel. And just like that, Kacchan was touchy with Izuku, too.
"Thinkin' too loud again, nerd," Kacchan groaned impatiently. He was sprawled out on the common room couch, head in Izuku's lap. Even this scene would've been enough to send either one of them - anyone in the room - into psychosis a year ago.
"Sorry, Kacchan," Izuku smiled down at him.
"Tch. Whatever. Just make yourself useful, got it?" Katsuki snorted, then grabbed Izuku's hand to thread it back into his hair. Izuku's smile only grew at the content sigh Kacchan let out when he resumed his task of carding fingers through blonde hair, occasionally letting blunt nails graze against his scalp.
Thus, another way Katsuki was channeling a spoiled house cat.
(Izuku had to keep himself firmly planted to the sofa to avoid running for his notebook when Kacchan groaned as he scratched behind his ears.)
3.
Now might be a good enough time to mention that Izuku didn't actually have much experience as far as cats went.
He'd never had any pets growing up. Of course, he'd longed for a furry soulmate, someone who could trail around with him, whom he could practice special tricks with for hours on end. He liked watching the stray cats that lingered on the street corner by the convenience store he and his mom frequented. The neighbors set out food for them, and Izuku had followed them once to their little shelter made of discarded blankets and boxes.
He learned quickly to approach them cautiously if he wanted a chance with them at all. Slowly, low to the ground, showing he wasn't a threat, wary not to startle them. He'd idly missed being clawed at once or twice by particularly irritable cats, but that didn't deter him from observing from a safe distance.
Once, he saw a gangly tabby enjoying a sardine on the cracked sidewalk. The treat was probably tossed away by a kid, or the old man living above the shop who liked to feed them. Whatever the case, the cat was in heaven, and munched on the little fish like it was its first meal in decades. When a spotted tomcat approached and decided it wanted a bite of its own, things turned into an all-out brawl.
Low growls rumbled, deeper than any sound Izuku thought the little balls of fuzz could make. They prowled around one another, fur sticking straight up, backs arched. Like calm before a storm, they stared one another down. When they finally lunged, the swats weren't anything like when Izuku approached too quickly, nothing like the quick daggered swipes at his arm. No, this time, they latched to one another, making more of those feral noises and sounding like they were committing murder.
It only lasted a few moments as they tumbled around, tails flailing and cries ringing up between the buildings. Izuku wondered momentarily if he ought to intervene, instinct encouraging him to take over and step in. But it was over as quickly as it began, and the cats scattered and went their own ways.
"Oi, don't eat crap like that, nerd!" Katsuki growled at him, and swatted an arm out to knock the freshly opened bag of potato chips out of Izuku's hands. The foiled bag went flying, and Katsuki's hands returned to his pockets.
"Kacchaaaan," Izuku whined. "I'm hungry."
"Yeah, yeah," Kacchan rumbled, and made his way towards the kitchen. "I'll feed ya, you incompetent bastard."
Izuku beamed at him. "Kacchan is so nice!"
"Shut up! I'm not nice."
"Heh."
Katsuki turned and strode back to Izuku, just to flick him on the nose, then followed it with a quick kiss. Izuku blushed and stumbled after him to keep him company while he cooked.
Kacchan was amazing at anything he did, but with cooking, he was a marvel. Izuku propped a hand up on his chin, forgoing even the All Might documentary Todoroki had put on in the other room to instead watch Katsuki deftly mix spices together, chopping vegetables, creating a beautiful, colorful, edible piece of art.
He sighed as he watched, earning small smirks from Katsuki every so often that he barely noticed as his eyes instead focused on long, manicured fingers stirring together the ingredients to their dinner.
"Oooh, what's on the menu tonight, Bakubro?" Kirishima strolled in and hovered just over Katsuki's shoulder.
"Nothin' for you, Shitty Hair," Katsuki told him.
"No fair!"
"Kirishima-kun can have my leftovers!" Izuku offered, sitting up in his seat to smile at his friend, who shot him a toothy grin and two thumbs up.
"Tch."
"Thanks, bro!" Kirishima leaned against the counter, joining Izuku's activity of watching their friend cook.
"Take a fuckin' picture. It'll last longer," Katsuki barked not a moment later.
"If you insist," Izuku said dreamily, and Katsuki just growled low at him again as he stirred the simmering pot on the stove. While he was busy, Kirishima took his chance, and grabbed for one of the peppers still sitting upon the cutting board.
"Oi!" Kacchan shouted, and grabbed Kirishima's arm. His muscled forearm flexed, eyes set in that crazed, determined look he got when he knew he was about to put someone in their place. Kirishima stood his ground, but neither activated their quirk, silent in their agreement on the test of raw willpower. Then, with just one brutal press of Katsuki's finger tips into the delicate veins of Kirishima's inner wrist, the pepper dropped right back down onto the cutting board. "Get your nasty sausages away from here," Katsuki said in triumph.
"Ew, Kacchan."
"Aw, man!" Kirishima whined, but took the defeat for what it was and plopped himself down in the seat next to Izuku.
It was then that Izuku remembered the cat fight over the sardine. And the quick swats he'd gotten time and again, forcing him to back off and give them space. He grinned and was out of his seat before he could think twice.
"Kacchan!" he yelped, and bounded over to the blonde. Katsuki raised a brow at him, impatient and eager to get back to the stove. Still, he was so handsome like this, wearing a cute apron that cinched at his already tiny waist. Izuku just wanted to squeeze him.
And, well, Izuku had never been one for self-preservation.
So, he indulged.
"Agh! What the hell, Deku?" Katuski jumped nearly a foot off the ground when Izuku pinched at the skin of his waist. He couldn't hide his giggle.
"You're just a cutie," Izuku smiled broadly at him, and Katsuki's eyes softened, only slightly, before remembering he was supposed to be pissed off at him. Before he could get that far, Izuku leaned in and pinched him again. Not too hard to hurt. He never wanted to hurt his Kacchan, but there was nothing wrong with poking a bit of fun at him like this, even if it was just to get a reaction, see what would happen.
"Fuck off!" Kacchan growled. And there it was, the small curve to his lips that accompanied those words when spoken to Izuku. He took it as a sign to crowd in on him closer, closing him in against the edge of the counter.
"But I can't help myself with you," Izuku said teasingly, and batted his eyelashes for good measure, just to really keep Kacchan on his toes. And with that, he planted a final pinch, this time on a nipple he knew was too sensitive for Katsuki's own good.
"Arghh!" Katsuki's voice was low and loud, and Izuku didn't need to jump back when the swat of the arm came his way. Kacchan would never hurt him intentionally, never again, and this was just a play swat. Still, it did the job of getting Izuku's hands back to himself. Kacchan was blushing furiously.
"Sorry, Kacchan," Izuku said through his laughter, and they both just gazed at one another for a few more moments. The rest of the room fell away, the low simmer of their dinner a comforting, familiar background noise. And deep crimson eyes, warm and inviting. Izuku's favorite color, his very favorite thing.
"Nerd," Katsuki grumbled out, then pulled him in close by the waist, planted a wet kiss to his mouth, paired with a quick squeeze to his hip that caused Izuku to yelp, and, yeah, he deserved that.
Still, he couldn't hide his smile as he made his way back to the table next to an amused Kirishima (who was long used to their antics and blatant flirting). He grabbed out his notebook and scribbled his latest findings.
4.
Kacchan claimed he liked to go to bed early, but it was really just a cover for his extensive night time skincare routine.
True, he was always so well-rested that it left Izuku envious, forcing himself under his own blankets at ungodly early hours to try to take a page out of his friend/rival/lover's notebook. But all he ever accomplished was a restless mind, frantic tossing and turning.
So, he gave that up pretty quickly.
Still, he loved spending time with Kacchan, and sleeping with him was another perk of the newfound level of their relationship. It was only natural for Izuku to smile affectionately at Kacchan's tired yawns when he tried to stay up late for Izuku's sake, thread their fingers together and lead him up to his room.
Even when he seemed dead on his feet (Izuku shuddered, shoving the poor choice of words away, away, away), Katsuki was never too tired for his routine. It was admirable, even if it meant Kacchan was stubbornly grumbling at his exhaustion, willing it to go away for just a few more minutes while he finished washing his face, brushing his teeth, endless battles to be won even in the warm bathroom light.
The boy simply couldn't finish his day until he had that final reset. Izuku had tried keeping him in bed after they'd fallen asleep once, the movie they'd been watching still rolling, forgotten in the background. Tugged him back into his embrace, whined protests and pleas to get him to stay, just hold Izuku for the rest of the night. But he always tore himself away eventually, untangling their limbs, leaving Izuku pouting in their nest of blankets and pillows.
Curiosity won out over Izuku's tiredness, and he perched the pillows just right so he could watch as Kacchan worked himself out of his slumber to tug his shirt off, pull his hair back in an All-Might themed headband Izuku didn't even know he owned. The shelves above his sink were meticulously arranged full of different products and bottles Katsuki seemed to know front and back, and muscle memory took over as he grabbed one down at a time.
He leaned over the sink, broad shoulders flexing as he scrubbed at his face gently, longer than Izuku himself had ever washed his face for. Next, he took a washcloth, wet it down, and ran it along his chest and the back of his neck. Izuku had no idea what the other products that followed the face soap were. Some clear liquid he dabbed onto a cotton swab, wiping it all over his face in gentle circles. While that dried, he loaded up his toothbrush with a simple white paste he insisted did a better job cleaning his teeth than any of the fancy sparkly shit. Izuku believed him, blinded by his smile as he always was. Kacchan was aggressive with everything that he did, but was surprisingly gentle when brushing his teeth. Izuku giggled at the memory of when Katsuki used to chew and destroy his toothbrushes relentlessly growing up, and the way he'd wailed when he found out he'd gotten cavities due to the harsh brushing. But he was quick learner in anything he set his mind to, and had the most beautiful smile Izuku had ever seen since.
Kacchan was also very adamant about flossing. Every night?! Izuku had exclaimed once, when Katsuki was staying the night in his room downstairs and had to run back up to grab some spare floss. Duh, ya gross nerd. Can't skip it. Feels weird. Izuku had gotten used to keeping extra floss around for Kacchan, who actually flossed multiple times a day, not just every night, and had even gotten into a better habit at it, himself. He tried to mimic the way Kacchan flossed. How he got up close to the mirror, eyes scanning each and every tooth, making sure each met his incredibly high hygiene standards before nodding curtly, and returning to his skincare. But still, he watched him now, just in case Kacchan had any other secrets Izuku could glimpse.
Thanks to his amazing quirk, Katsuki already had perfect skin, so Izuku wondered why he went through all this effort every night. He loaded up his fingers with lotion, placing it delicately onto his cheeks, to the tip of his nose, and his forehead, then slowly rubbed it in. Izuku's skin got so oily if he used too much moisturizer, and he wondered how it was that Kacchan could layer so much onto his skin that was already so frequently coated in sweat, yet didn't seem to need any cleansing whatsoever.
But, with everything that had to do with Kacchan, the more Izuku watched, the better he understood.
It was the end of the day after a frustrating patrol. Nothing too major, just an aggravating low-level criminal who found it entertaining to hurl poor-tasting insults at Katsuki, bullshit about him resembling a villain. It was an old wound, but stung all the same. As much as Izuku fumed (and may or may not have knocked the guy on his ass), and as much as he planted soft kisses to Katsuki's cheeks to coax him back to the present, nothing seemed to settle him. He was wound up, a crease making a home between his brows, scowl permanently etched onto his face.
That is, until his night time routine.
It was a wonder how something so trivial could have such an effect. But, if Izuku thought about it, he supposed he was similar in his own way, with his notebooks he kept. When his mind threatened to buzz away from him, take him up, up, and away into a tornado of thoughts and emotions, he simply grabbed his pencil and a notebook to ground himself.
Maybe that's what this was to Kacchan.
Because there he stood, absorbing the lotions and oils into his skin better than he'd taken in any of Izuku's loving words. Whatever worked to get him out of that funk, Izuku was more than alright with, and he was content to watch, smile returning when that tension finally seeped out of Kacchan's shoulders as he finished up.
"Feel better?" Izuku asked, and reached a hand out to cup his cheek, only to meet another scowl on Katsuki's face. He swatted his hand away before it could make contact with his jawline.
"Oi!" Kacchan barked. "You wanna undo all that shit I just did in there?"
Izuku giggled, and leapt up to wash his hands thoroughly. But even then, Katsuki swerved from his prodding fingers, and settled into his clean pillowcase instead.
That night, as Kacchan surrendered himself to peaceful dreams, Izuku scrolled away on his phone (it was still too early for him to sleep), reading up on cat grooming habits.
5.
"Kacchan!"
"Mm."
Izuku struggled against the heavy grip, willing himself to gulp down bites of air as he wheezed.
"Argh, Ka-!" his voice cut off, dissolving into another fit of giggles as Kacchan traced his fingers against Izuku's sensitive skin of his abdomen. Blonde spikes poked at Izuku's eyes from where the other boy nuzzled into him, as though he wanted them to blend into one.
"Take it, nerd," Kacchan's voice was muffled, and Izuku shivered at the brush of soft lips along his neck.
"Wah!" Izuku cried out before another laugh was pulled out of him thanks to Katsuki's unwavering tickles. "Play nice, Kacchan!"
"No way," Katsuki smirked against him, and followed it with a quick nibble to where his jaw met his ear. "You're mine. I can do whatever I want to you."
Izuku melted at the words.
Despite his taunts, Katsuki finally relented, letting Izuku breathe again. His throat felt hoarse from laughing so hard, but he could still feel that smile against his skin, so it was worth it. Kacchan was already splayed out on top of him, and Izuku wrapped his arms around him to pull him in even more.
"Sap," Kacchan murmured.
Izuku only pouted. "You're the one who initiated a tickle fight, Kacchan."
"Yeah, and what of it? Nothin' sappy about that. It's got fight in the name."
"That doesn't make it an un-romantic couple activity."
"Tch."
Izuku just giggled, that smile pressed into his neck again. But instead of retreating this time, it lingered. Kacchan's lips were always so moisturized, and Izuku couldn't help from tilting his head to give him better access, hoping he'd trail firm kisses down to his collar bone, along his chest, all over his body.
But Katsuki just nuzzled into him again. Lips fell away, and Izuku felt the press of his forehead into the spot where his mouth had been, rocking gently from side to side, just the smallest of movements. Each one had Izuku squinting at the hair, unruly from their aggressive cuddling, that poked at his face.
Kacchan's sigh was content, and his muscles unwound as he settled in. Izuku would have no problem sleeping like this through the night, but Katsuki was incredibly particular about his sleeping arrangement, and likely wouldn't even fall into a nap in this position. And yet, he stayed, warm breath kissing Izuku's nape.
Their legs were tangled up; they knew exactly how to fit into one another now. Though, it hadn't taken long to learn in the beginning. They just fit so naturally, with Kacchan's lean frame weaving around any bit of Izuku's stockier build he could reach.
He could tell Kacchan was still awake from where he rubbed his toes gently along Izuku's shin. As though, even in their utterly relaxed states, Kacchan still wanted Izuku to feel his affection in any way he could give it to him.
(Because plopping down on top of him like this wasn't enough, apparently.)
(Not that Izuku was complaining.)
Sometimes, Izuku found himself getting that way, too. When his feelings filled up to the brim and overflowed, and he had no idea how to get them out, leaving him frazzled. At that point, he was beyond words, or even attempting to write them down. Instead, he'd bounce around, get his energy out that way, run a few laps, maybe even challenge Kacchan to a friendly sparring session just to have an excuse to get his hands all over him and squeeze.
In those moments, Izuku felt like he had so much love for Kacchan, he couldn't breathe. It wasn't a weight, or a pressure on his shoulders, but an inevitability. Something wondrous and beyond his own understanding, something no amount of research and experimentation could explain away. So, he didn't try to, content to let his affection overflow into little moments of loving aggression that Katsuki seemed to slurp up eagerly, because it was a language he understood.
Maybe that's where Izuku had learned it. They'd grown up together, been side-by-side for so long. Was it really so far-fetched that Izuku had integrated bits and pieces of Kacchan's being into himself? Their souls were already woven together, twin stars roaming the galaxy forever, so of course Izuku's body learned to explain to Kacchan all the ways he loved him in a way that was just for him.
And maybe, that's exactly what these soft moments were, too. Kacchan having a piece of Izuku within him, holding it close, cherishing it, loving it. Letting it grow and grow and grow until he couldn't keep it in anymore, and had to nuzzle in close, burrow into him, give way to cuddles he'd once been so against.
But then.
A warm nose pressed against Izuku's neck and inhaled deeply. Held there, then let out, the body on top of him melting into him even more. And just like how he'd rubbed his forehead on him, Kacchan's nose did the same thing, lips dragging as he pressed in closer.
Still, it wasn't enough. Katsuki was leaning in, the bridge of his nose pressed into the crook of Izuku's jaw. He breathed deeply, as though Izuku was the only oxygen he needed in this little planet they kept to themselves. And when Izuku nuzzled him back, Kacchan sighed contently, then went completely boneless.
And he fell asleep.
Breathing even, soft snores.
Izuku didn't think he could be more in love.
Careful not to wake the slumbering boy, Izuku grappled for the notebook he'd stashed under his pillow, eager to update his latest findings. He'd gone down a rabbit hole the other day on cat habits, and chuckled when he found something called 'bunting', or when cats rubbed up against someone to scent them. Mark their territory.
Izuku felt very much like he belonged to Kacchan in this moment.
Well, every moment.
But especially this moment.
With one arm still wrapped around Kacchan, he jotted down every detail of the possessive movements he'd just been on the receiving end of, smiling as he was nearing his conclusion. He had no idea what next steps would look like. Maybe he'd do more research, see if there were other ways he could reciprocate, or let Kacchan know he saw him, understood what he was trying to say? Or maybe there was something about the way—
"Hah?!" a harsh voice jolted him from his thoughts. "The fuck is this?"
Before Izuku could react, Kacchan was swiping the notebook from his hands.
"Ah! It's, uh, nothing, Kacchan! Just something silly I'm working on! Really, don't worry about it—"
"Deku," Katsuki silenced him, and Izuku hid behind his palms as the boy flipped through pages and pages of findings. Behaviors and patterns recorded, Izuku's own observations and hypotheses, even little sketches of how Katsuki napped in the sunlight. When he got to the title page, he scoffed.
"'The ways in which Kacchan is a spoiled house cat'? The fuck, creepy fuckin' nerd! I'm not a fucking cat!"
"It's not literal, Kacchan," Izuku scolded him as he snatched his notebook back, lovingly fixing a bent corner of the page where Kacchan gripped too hard. "But you can't lie. It's pretty accurate."
Katsuki looked like he wanted to set something on fire. Maybe the notebook.
"No. If anything, I'm a wolf."
Izuku cracked up at that, and Katsuki growled at him, offended.
"Big, scary wolf Kacchan?" Izuku teased him, and leaned in close, so they both went cross-eyed.
"Yeah, dummy. Though you were supposed to be smart or somethin'."
"You wouldn't be with me if I wasn't."
Katsuki blushed at that and looked away. "Whatever, nerd. Take your weird fetish notes. Always knew you were a freak."
"It's not a fetish—!" Izuku wailed, but Kacchan just rolled his eyes and tucked himself back into Izuku.
"Shuddup. Tryin' to sleep now, 'Zuku," Katsuki murmured. Mindlessly, he rubbed his face against Izuku's neck again. "Hold me, dammit."
"Kacchan!" Izuku laughed, arms returning to their rightful place around the blonde. "You're literally marking me with your scent right now!"
"What?! The hell I'm not!" Katsuki denied it, but he didn't move away.
"Then what are you doing, huh?"
Quiet. And then, Kacchan spoke in his softest voice. "Dunno… feels nice."
And how could Izuku argue with that?
+1.
It was the anniversary of the final battle against All For One.
No one slept well on this night. Even though years had passed, and no one had it marked on their calendar, somehow they still knew. Like a fog settled into their bones the moment they woke up, and followed them around all day, unwilling to be forgotten.
Things had gotten easier with time. But it still lingered.
Some fared better than others.
"Kacchan!" Izuku choked out, chest rising but never drawing a full breath. Everywhere he looked, he saw his love's body, cold and unmoving. He waded through the hallways of unpleasant memories, tripped up the stairs as he tried to claw his way out, until his nails gripped the familiar wooden pattern of Katsuki's door.
"Deku?" Katsuki's voice was laced with sleep.
"Kacchan," Izuku sobbed in response, collapsing into welcoming arms, a strong and healthy and warm warm warm body.
"Hey. I've got you, okay?" Kacchan murmured into his temple. He guided him to the bed, let the familiar softness of his too-hot comforter blanket him. "I'm right here, 'Zu. Not goin' anywhere."
Izuku's cries slowed, but didn't stop. Couldn't. Not quite yet. It felt good to let it out. Not like earlier in his room, when the darkness felt like an ominous permanence, and Kacchan was so far away. But here, he was safe; they both were, because they had each other, and nothing else could touch them.
Minutes passed, and Izuku gradually collapsed into Katsuki. Firm, unwavering, amazing Katsuki.
Izuku loved him so much that it hurt.
"There you go. C'mon, ya nerd," Katsuki said affectionately, and Izuku was struck by how lucky he felt. To be here, to be alive, to finally be in Kacchan's arms like this. He belonged here, he knew that now, didn't ever want to be parted from him.
"I love you, Kacchan," Izuku tried to say, but it sounded more like a croak. Katsuki heard it, though, and hugged him tighter as he pulled the blankets up around their interwoven bodies. He let out a soft hum as Izuku began to relax, head falling heavy onto his shoulder.
Sleep was too far out of reach, but that didn't bother Izuku. He had no interest in returning to the land of nightmares, and was much more content to watch Katsuki's eyelashes flutter in the dark, run fingers along his skin to see goosebumps grow and disappear.
The nuzzling became a common behavior.
Izuku really liked it.
He nuzzled Kacchan back, even as he felt the other boy steadily approach sleep again.
It was so easy to love Kacchan. To look at him, and see how wonderful he truly was. Beyond the obvious quirk and confidence, there were mountains of intentionality, careful deliberation, wisdom and cleverness that no one else came close to. Izuku was thrilled by it constantly, never able to get enough.
Kacchan had died to save thousands. To save him. And Izuku had already vowed to spend the rest of his life—and any subsequent lives where they'd inevitably find one another—and show him how much he loved him. How his efforts hadn't been in vain. Because even though Izuku was beyond pissed that Katsuki had gotten himself into a situation that had led to his death, even though he'd wanted to yell and scream even back when he'd dived in front of Izuku to get himself impaled, Izuku knew he would've done the same exact thing.
And Kacchan knew that, too.
A constant race of trying to outpace each other, if only so they could be the one to provide the other protection.
Fucked up, sure. But they didn't know any other way.
Well, except for this.
Fingers trailing through Katsuki's hair, earning subtle groans out of the back of his throat. Izuku knew all his sweet spots now, and smiled through his drying tears at the person he worshipped next to him.
Because for every kick, punch, abrupt tackle to the ground, screaming matches and misunderstandings they'd had growing up, they had a thousand little butterfly kisses, or constellations traced out of freckles and scars, all to make up for the years of hurt.
I love you, Izuku whispered over and over again into the night, wondering if Katsuki was still awake enough to hear it. If the words would meet him in his dreams, keep the nightmares away.
Those groans still rose steadily from Kacchan, especially as Izuku traced the curve of his ear, or pressed chapped lips to his soft cheek.
"You're purring now," Izuku giggled wetly. He was still crying, but the tears weren't sad or scared anymore.
"Am not," Katsuki groaned, half asleep. But still, his thumb rose up, dusted away the tears. Ran over the seam of Izuku's lips.
"You are," Izuku insisted, because he liked being a little shit, and knew Kacchan liked it, too.
"Mmm," Katsuki grumbled lowly as Izuku dragged nails along his scalp. He was close to preening now, the corners of his lips curled up in satisfaction.
"See!" Izuku laughed. "What else would you call those noises, Kacchan?"
"Whatever, nerd," Katsuki said, and he didn't even pretend to sound annoyed at this hour. Not when Izuku was laughing again, and the tears were slowed, and they were holding each other knowing nothing would tear them apart again. "You feel good."
"I like making Kacchan feel good," Izuku said, and pressed a long kiss to his mouth before cuddling up on his chest again.
"Mmmm."
Izuku tried to stay quiet. He had to stay quiet. It was the middle of the night, and he was so comfortable, and Kacchan looked so peaceful. He absolutely could not get up and run down to his room to grab his notebook and make more notes about all these adorable little noises Kacchan was making because Izuku was just touching him—
"Oi, enough!" Katsuki growled, and planted a firm kiss to stop Izuku's mumblings. "No notebook. You can write this shit down in the morning."
Izuku blinked, eyelashes brushing the delicate skin of Katsuki's neck. "Does… does this mean Kacchan thinks I'm right?"
"Tch."
Perked up and fully awake again, Izuku loomed over Katsuki, searching his sleepy features. He was so handsome, bed-head a perfect crown around him, pajamas ruffled and draping off his shoulder. Izuku brushed a thumb along the sharp curve of his cheek, and Katsuki whimpered.
"Hah!" Izuku cried out, triumphant at last.
"Shut it! You didn't hear shit! Back to sleep, nerd!"
"Okay, Kacchan," Izuku relented, and finally settled in to try to sleep. It was easier in this room, with Kacchan holding him. With his own arms wrapped tight around his waist. Their breathing matched up, mirroring one another, pattern so familiar that Izuku wondered if there ever could've been a time when they didn't do this.
Loving Kacchan is so easy.
Izuku's smile followed him into sleep.