im interest in the idea of abo au where bkdk accidentally bonded v young but katsuki spent years suppressing it bc he's not going to be tied down by a useless, quirkless omega. then they got into UA & forced in close proximity, trying to keep their bond a secret from others...

they still have that push and pull rivalry, and resentment mixed up with admiration that dominate their entire relationship where nothing really changes even though they're a bonded pair, still going at each other like they'll pulverize the other's face to the ground lol

but now it's also anchored by a mating bond between them that has katsuki knowing izuku's exact heat schedule so even if he doesn't mean to he'll bring izuku an old well worn shirt smeling of him and when katsuki go alpha feral izuku is the only person who can calm him down.

like, bkdk is still v much clumsily trying to repair their broken relationship with katsuki still holding all these bitter and complicated feelings toward izuku and izuku long ago had given up the idea of being katsuki's *mate* & settled (hopefully) for his friendship instead.

it's just now they have to deal w a mating bond that tell them they should get the fuck on and like bare their souls bc nobody can ever come close to what they are to each other all the while they're just trying to learn to exist in the same space w/o breaking into a fight lol

tho they were bonded and tied by their abo dynamic it doesnt defined them nor their entire relationship w each other bc they both had chosen to put that bond in a state of permanent stagnation if possible. it's pushed to the background as they pursue their dream and each other

by all accounts the nature of their bond and the way it set in so young they are a true mates but that's not love. how can it be when they were too young to even understand and consent to such a bond forming between them. that's why society frowns upon children bonding so young

it can be damaging bc it's irreversible. the media like to promote that finding your true mate and bonding ever so young is v romantic bc here is this one person who is practically conceived to be your perfect partner down to their dna makeup. they are yours & you are theirs.

but for bkdk whose silly childhood mistake cost them nearly everything bc now they're stuck w each other & what they have is instinct, a basic drive to be together but what they both want is a choice. the choice to choose each other instead of having that choice forced upon them.

katsuki who always done things his way & never like having things decided for him hated their bond the moment he realized what it meant. izuku being quirkless was already terrible already but now he's stuck w dumb useless deku?? FOREVER? FUCK THAT. why is he responsible for him?!

bc any person w any sense knows the alpha is really the one beholden to the omega. it's just another chain of an unending linked of chains that bind him to izuku. so katsuki's resentment is deeply rooted even more bc he cant seem to get rid of izuku no matter how hard he tried.

izuku may have been caught up in the idea truemates like all the stories his mother told him but during the worst yrs of his life when katsuki had spurned him & hurt him w his words, he thought to himself if being truemate meant being hurt like this then maybe it isn't worth it.

bc while he admires katsuki deeply and doesn't hate him for his prior cruel actions and words that had cut deep bc how could he when neither of them were aware enough to choose this, choose each other, and izuku wouldn't choose himself either if he had the choice.

but while he wishes ardently for their relationship to mend and have katsuki's friendship once more but he doesn't think he can trust katsuki with his battered and bruised heart again. they're truemates but katsuki has yet to earn the right to his heart. not like this anyway.

so even tho bkdk aren't in love w each other it doesn't stop their bodies, hormones, from drawing them to each other. like, how katsuki will know down to exact hours when izuku's heat will hit & how his scent go sour in respond to izuku's anxiety but it's all INSTINCT

izuku's omega will claw & hiss when katsuki's attention is focus another person & when he's stress, izuku knows it just from tug of their bond.he wants to crawl over & tucked his head under katsuki's chin to calm him down but it's ALL INSTINCT. izuku has no right to do any of it

they're barely friends as is, still a WIP, so while their body are in sync & so tuned into each other as though they are 'one' it take their heart A LOT LONGER to catch up & fall in love bc they both had to grow up and into the person they always meant to be for that to happened.

bc truemates doesnt (always) mean true love. it means they're the most compatible to each other. their biology speaks for themselves, but humans aren't just their abo dynamic and their biological imperative; they hate, love, and feel so fiercely that it overrides all sense.

and bkdk are the most stubborn shitheads in the world so when they're determine not to be 'together' in that truemate bonded bs way that society romanticized, they both choose to ignore their bond w each other and blatantly pretend it doesnt exist... except it v v much does lol

izuku's routinely gets heat where in his most delirious and desperate state he's only know how to called out one name and katsuki somehow always, ALWAYS find himself in front of izuku's door, never going in but waiting outside each day as though his presence there can calm izuku

even if it's only briefly, even if he can only give izuku his shirt but NEVER HIMSELF. it's the kindest act katsuki had ever done for izuku and for that izuku will forever be grateful to him. he may not have room in katsuki's heart but in this moment katsuki is his and only his.

in this moment of hormones and willful ignorance to anything but what his body craves and needs, izuku can delude himself to thinking that in world where they weren't hindered by their past hurt, maybe they would would have chosen each other and they could have had this

but all they have now is this wall that stand between them & what they could be bc they never share a single heat or rut w each other. some of it is bc they dont want others to know but mainly bc they cant afford to sink deeper into each other by given into alpha/omega's instinct

so they have a tentative silent agreement that this will be their secret and theirs only. even the school officials of UA aren't aware that they have two bonded mates under their midst bc bkdk doesn't want their bond to hindered their advancement toward their dream.

eventually thru A WHOLE LOT OF TRIALS AND ERRORS AND BUMPS IN THE ROAD bkdk slowly developed feelings for each other over time but it has nothing to do w their abo dynamic; it's just them seeing the best and worst of each other and saying THIS TOTAL DISASTER, I LOVE HIM.

but by then, izuku already made up his mind that he may not have katsuki's love but at least he has katsuki's friendship and this bond that nobody can break and so even find another person to love it'll be OK while katsuki is like MINE MINE, his stupid alpha roaring back to life

he spent so LONG suppressing his alpha instinct around izuku that when he finally acknowledges that he care for izuku in *some* way that maaaybe romantic now lol the alpha side of him is like a chained beast unleashed into the world for the first time and it's wont be tame again

bc katsuki refused to treat izuku as his omega in the past even tho he had payed special attention to izuku during his heat but that's just dumb biology doing the work he doesnt care if izuku mate w another person, or even another alpha; izuku's business is his own not katsuki's

but now that the beast is out and had sink it claws into his chest, katsuki is completely unbalanced and undone bc he starts behaving like some dumb alpha trying to court their omega for the first time, cooking for izuku, paying attention to him, being THOUGHTFUL AND OVERBEARING

in that aggressive ways that he is, only compounded by this awakening in him. so much so that for the first time when izuku's heat hit he thought about offering to help izuku w it bc a heat w an alpha esp A BONDED OMEGA LIKE HIM is excruciating like ten lvl of hells painful

izuku has been doing this *alone* for so many years QQ. he never complained and never ask katsuki to help him out. not even once in most desperate moments when the pain is way too much and death seems easier. so katsuki shyly & clumsily offers to help izuku out in one of his heat

but izuku shakes his head and firmly tells him, "I only want to share my heat with the partner i have chosen" and that's the cruelest and kindest rejections katsuki had ever received and he wonders if it's karma for all the time he was the one to reject izuku in the first place

it's in this moment that he realizes that their body had long chosen each other long ago and biology had set them as the *perfect* match for each other but their hearts had to struggled & be earned before it can finally catch up to what their body have been telling them for ages

so yea maybe biology is fucked up and shouldn't be the deciding factor on who they should be w. katsuki had resentment it at first and still resent it now bc it should have BEEN UP TO THEM but that choice was taken so now they have to fight harder to be w each other

to prove that that their feelings are worth every bitter fights and hurt bc katsuki doesn't give a fuck about biology whether they're truemates or not bc he chose izuku now and in the future and that choice means he's going to do everything to earn that right to have izuku!!!!