Thread by @skyfallgar1

#CSLCelebrates #KatsukisBirthdayBlast
i know i'm a bit late but here's my bkdk vampires au inspired by the prompts of this event

tags: #bkdk, #dkbk, vampire!bkdk, immortal!bkdk, pranks, comedy, crack

summary: vampires bkdk who keeps pranking each other every 50 years or so

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- day 1 - the original prank -

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izuku barged into their shared home, panic written accross his face. "kacchan! we have a problem."

"no," katsuki shrugged. "YOU have a problem." he then pointed a finger to the intruder. "i have an idiot who keeps getting into one."

"mean, kacchan," izuku pouted.
"so, what is it this time?" katsuki asked.

"i told vampire hunters we were vampires," he blurted.

"you did WHAT??" katsuki stood up. "wh- why the fuck would you do that??"

"but it was a prank!

i was supposed to tell them it wasn't true after they freaked out! but they didn't let me! they said things like 'i knew it!' or 'i told you so!' and then they were talking about an investigation they had running on us! and then they started attacking me!

and then I had to run away! and then it was supposed to only be a prank!" he cried.

katsuki stayed silent after that, staring at izuku in disbelief.

"kacchan, please say someth-"

"you're right," katsuki interrupted him,

"we got a problem. the problem is that i have an idiot who keeps getting into one."

"i'm sorry, i didn't mean to!" izuku cried again.

"you told them we were vampires!"

"because it was a /prank/!"

"but we /are/ vampires!"

"well-" izuku scratches his neck.
"a prank is about making someone believe something and then it turns out it's not true!"

"maybe I should've told them we were werewolves, it would've been funnier since they don't hunt werewolves..." the smaller boy mumbled.

"no! you- god! deku! you're so fucking stupid."

"mean, kacchan," izuku pouted again.

a quiet silence settled between them.

"wanna run away together?" katsuki finally asked.

"yes!"

and then they left.

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- end of day 1 -

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- day 2 - the revenge prank -

"remember when you told vampire hunters that we were vampires and we had to move out?"

izuku sighed. "it was 200 years ago! are you still mad at me?"

"not really," katsuki replied. "i just thought that I could show you what a prank really is."

"what, you're gonna tell vampire hunters we're werewolves?"

katsuki threw him a judging look, "was that joke funnier in your head?"

"it's funny outside my head too!"

"sure," katsuki snickered. "anyway, i need to go de-stress," he added, standing up and moving toward the exit.

"where are you going?" the other vampire asked.

"to demolish the living room," he laughed.

izuku rolled his eyes, "you're not that good at pranking either, kacchan."

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when izuku got back to their shared appartement this night,

he was met with the sight of a entirely destroyed living room. the tables were flipped, the couch entirely lacerated and all the beautiful frames who used to once decorate their walls were shattered on the ground.

he immediately started panicking, thinking of the worst. "kacchan!" he called worriedly.

"deku? you home?" katsuki's voice echoed from the kitchen.

"oh my god, kacchan!" izuku ran to him. "are you okay? what happened?"

katsuki ignored him, grabbing the curry from the shelves before adding it to his preparation.

"kacchan?" izuku tried again.

katsuki turned to him and smirked. "so, how do you like the new agencement?"

"what new agencement? you- you're the one who did this?!

the living room is completely /demolished/!"

"i told you I was going to do it."

"but you made me think it was a prank! /this/ is not a prank! you said a prank was about making someone believe something before it turns out it's not true!"

"well, i made you believe that i wouldn't do it," katsuki explained, as he was finishing his cooking, before handing a plate to izuku. "and it wasn't true. it's what a prank is about, right?"

izuku stared at the other vampire in disbelief,

katsuki still holding the plate for him.

okay," he eventually said, "you got me real good this time."

he then took the food katsuki had prepared, moving toward the thrashed living room to eat his dinner among the destroyed furniture, katsuki in toe.

since neither of them wanted to clean the mess katsuki had made, they moved out the next day.

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- end of day 2 -

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[a/n]
- bkdk are childhood friends
- katsuki was born a vampire
- izuku became a vampire later
- a lot happened then, their relationship used to be like their canon middle school selves since katsuki thought that vampires were superior

[a/n]
- they eventually became friends again
- they live together, but since they're immortal, it doesn't worry them when the other disappears for a few decades
- now they're sending each other postcards when they're away
- they're old

[a/n]
- the first prank happened in germany during the XVIth century
- the second one in england during the industrial revolution
- in this au, vampires don't burn when exposed to the sun, but they dont particularly like it because sunlight makes them sleepy

- day 3 - the bridge prank -

the bridge was huge. immense even, its parabolic arch spanning a tumultuous river, a massive pillar standing at its exact center, several stays anchored at each side, meant to support the road deck.

the bridge was so tall that even the trees around couldn't compete in term of height.

its steel framework was flawless, the red beautifully contrasting with the colours of the forest.

izuku had said he would be waiting for him at the top,

told him he had a surprise for him there.

with a sigh, katsuki began to climb.

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it took him /hours/. when he finally made it to the top, he saw izuku waiting for him on the plateform.

"you made it, kacchan!"

"yeah, where's my suprise, deku."

"there isn't one!" izuku replied with one of the brightest smile he ever saw.

"what?"

"it was a prank!"

"what?" he repeated.

"yeah, remember that time 100 years ago when you made me think you wouldn't destroy the living room, but you actually did?" izuku explained excitedly.

"well, i told you i had a surprise for you here, but i don't!"

"so because i ruined your couch a /century/ ago, you found a random brid-"

"not found," izuku interrupted, "i built it."

"you /BUILT/ a bridge in the middle of the forest and made me climb it?! for nothing?!"

"not for nothing, for a prank!" izuku beamed. "and for the beautiful view?" he added when katsuki didn't reply. "i thought you would like the view."

"deku," katsuki managed to say, despite the mix of confusion and irritation that had taken over his brain,

"right now, i don't know if i want to kiss you or shove you off the bridge."

"can i pick?" the fucker had the audacity to ask. "i wanna kiss you."

katsuki sighed and marched toward izuku. he cupped his lover's cheek in his hand, slowly approaching his face to his,

izuku melting into his palm. when their lips brushed, he stopped.

"i don't," he said and, before izuku could react, he shoved him off the bridge.

"idiot," he laughed as his companion was crashing into the water.

he took a look at his surroundings. izuku was right,

the view was truly beautiful.

watching the sun set and the sky turn red, he sighed, "how the fuck do i climb that shit down now?"

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- end of day 3 -

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[a/n]
- katsuki ended up jumping into the water because it was the easiest way
- the bridge is inspired by the garabit and the millau viaducts (i'm 100% the bridge i made wouldn't work and that it would break one way or another)
- i made a drawing of the bridge

- day 4 - the race prank -

the life of a vampire could sometimes become a very lonesome existence.

watching the years, decades and centuries pass, hearing history being told, forgotten and repeated again, witnessing births and deaths of civilization,

meeting people who were born and died without any consequences on the string of time could become quite overwhelming. it brought izuku an emptiness he didn't know how to fill.

that's why he was glad to have a companion by his side. well, most of the times.

because, as they were lost in the middle of nowhere, surrounded by only ice that couldn't be broken, said companion was quite... irritated.

"you and i are the modern day romeo and juliet", katsuki said.

"awww why?" izuku asked playfully.

"is it because we're destined to be together?"

katsuki threw a glance around them, making a dramatic gesture toward their surroundings. "no, it's because we're the two biggest idiots i know"

well, he wasn't wrong. it was their stupidity who put them into this mess.

"but for some reasons, you still are able to surpass that idiocy and put us in fucked up situations like this," he continued. "antarctica, really?"

"yeah! what do you think?" izuku asks with a bright smile. "we're actually standing exactly where the south pole is.

i chose the geographic one rather than the magnetic because i wanted us to be at the exact point where all meridians meet, this way, no matter the direction..."

katsuki let izuku excitedly ramble about the specifics of his pranks,

listening curiously, but something didn't add up. usually, izuku would just drop him to a random place and wait for him, lazily relaxing at home.

"why are you here then?" he asked when the rumbling died down.

"oh," izuku replied, holding a chuckle.

"i didn't know how to make the ice-breaker ship make a half turn. so i stayed."

"you're a fucking idiot," katsuki sneered.

"yep," izuku beamed, cheerfully. "but it was a funny idea, right?"

katsuki simply huffed in return. "it was fucking stupid."

it was starting to get a bit cold.

"so, since we're both stuck here, we could team up. there's ice cream home."

"i think there's enough ice here for us already."

katsuki paused an instant, looking at the extensive stretch of ice around them. after a few minutes, he turned his gaze back to izuku and grinned.

"we could team up... or we could /race/."

"what?"

"we could race. the loser has to give up prank privileges for the rest of the century."

izuku stared at him for a moment, internally weighting the pros and cons.

"deal," he finally said. "i'm going north and you're going south?"

"you're a fucking idiot,

you brought us to the geographic south pole. we can't go more souther."

"souther isn't even a word, kacchan."

"it is now. because if your stupidity."

izuku rolled his eyes before pointing his finger to a random direction. "i'm going this way then."

"suit yourself," katsuki said. "i'm going the opposite."

with a quick move, he tripped izuku and turned the other way.

"enjoy your second place," he yelled as he started running.

katsuki ended up the one winning, but when izuku came home, he wasn't alone. with him was a little vampire kid he had found along his way home.

"idiot," katsuki smiled.

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- end of day 4 -

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[a/n]
- izuku pointed to the most farthest direction to home
- they have several house accross the world and went to the wrong ones first
- the kid is eri
- he found eri hiding in the first one he went to
- it was the one with the destroyed living room

[a/n]
- eri helped katsuki with his prank for the next century
- it was the first thing i wrote about this au

[a/n] here's the difference between geographic and magnetic south poles for those who are curious

- day 5 - the kidnapping prank -

sharp eyes were looking at him, glowing in the dark. he stared back at them with the same intensity, trying to growl at his ravisher, but the tie on my mouth wouldn't let him to.

the man in front of him moved,

toward him and snatched the gag away.

"we got to stop meeting like this," he grinned.

"you kidnapped me, fucker," katsuki snarled, aggressively pulling on his restraints.

"really? i just wanted to bring you back home, kacchan."

"you /abduct/ me while i was on a vacation."

"you weren't on a vacation, kacchan, "izuku whined. "you were hiding from me, your own lifelong vampire companion."

katsuki rolled his eyes, "stop calling us vampire companion."

"bat-mates?" the other tried.

"what?"

"you know, the contraction between bat and mate."

"i'm so going to kill you."

"you cant," izuku said bluntly. "i'm immortal."

"vampires have nothing to do with bat!" katsuki shouted.

izuku nonchalantly shrugged his shoulders, "not my fault you're so scared of them."

"i'm not- i'm /not/ scared of them."

"really? so you don't mind if we get bat-pets?"

"deku," katsuki said. "untie me."

"no, i won't."

"deku," katsuki carefully repeated,

"i know you've just got your prank privileges back. and that you wanted your comeback prank to be awesome. and it was! but i was on a vacation with eri, and now she's all alone out there."

izuku raised a brow, "you took our daughter on a vacation to siberia?"

"yes! she wanted to come with me and I wasn't going to reject her," katsuki supplied.

"oh my, i wonder why she would," izuku chuckled.

the door of the room suddenly bursted open and a teenage girl with long silver hair and red eyes entered.

"yeah, i wonder why as well,"

she grinned nefariously.

katsuki stared at her in shock, his mind quickly connecting the dots.

"is that why you wanted to take your radio with you? so you could tell deku where we were? you traitor!"

"c'mon, dad!" eri laughed. "it was a funny prank!"

"yeah," izuku added,

"we made you believe that you could thrust your daughter and bam! turns out it's not true! that's what a prank is about, right?"

katsuki stared at them for a moment, his betrayed gaze going from one traitor to another.

"got me real good," he finally said.

"can you untie me now? i wanna go back to my vacation. alone. without any spy pretending they wan't to spend the with me."

izuku and eri laughed. "so dramatic, kacchan," his lover said, we're still in siberia, by the way.

i built us a house here, we're technically still on your vacation."

"yeah, dad!" eri beamed. "we're gonna spend time here together!"

"really? you wanna tag along with me? in siberia?"

"of course, kacchan. we're a family, right? we just wanna spent time with you!"

"i thought you didn't want to come with me," he mumbled. "is that why you kidnapped me? you just could have said you wanted to come along."

"true, but where's the fun with that?" izuku playfully retorted as he was undoing his restraints.

once he was untied, katsuki excitedly marched toward the entrance, eager to see the outside of their new home. but when he grabbed the handle, he turned to izuku, doubts suddenly clouding his eyes.

"wait a minute," he said, suspicious. "it's not another one of your prank again,

right?"

"you'll juste have to open that door and see by yourself, kacchan," izuku grinned.

katsuki inhaled deeply before kicking the door open. taking a breath of fresh air, he smiled when he saw the stunning aurora borealis lightning up the night sky.

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- end of day 5 -

[a/n]
- this one happened during the second half of the XXth century
- they're rich
- that's why they can afford to have so many houses accross the world
- each time they move to a new home, they keep the previous one "just in case"

- day 6 - the castle prank -

they shouldn't have let their guard down. they were the oldest and most notorious vampires this planet had ever known, they were feared and respected in every country of the whole world,

and they mastered the art of pranking and trapping like no one else could.

and yet, they had been tricked by a kid.

they shouldn't have followed kouta without questioning anything, they had let their heart take over their reason.

they should've known something was up, the household had been far two quiet those past weeks.

well, they knew something was up, they just didn't imagine it would be a trap that sophisticated, waiting for them to fall into.

katsuki was fuming.

"lemme burn that place to the ground," he yelled.

they've been trapped in this labyrinth for hours, and it didn't seem like they've made any progress so far.

"seeing that it's a castle made of stone i don't think it's gonna do much damage," izuku deadpanned.

"but trying will make me feel better," his companion grumbled.

they took another turn, just to see it was a dead end. again.

"do you think they forgot to add an exit?" izuku asked.

"shut up," katsuki retorted. "you're going to bring back luck on us."

"it would be such a shame. that labyrinth-castle is absolutely stunning, can you believe it! the fact that the kids built this by themselves is very impressive."

"don't look so proud of them, you fucker." katsuki growled. "we're trapped in here if i have to remind you."

"but it's so cool! you're just mad, because the kids chose to take after me and not you! they're building things like their papa, i'm so proud of them," izuku said, shredding an emotional tear.

"you're such a crybaby," katsuki grumbled.

"they even add those beautiful drawings on the wall! they really thought about every little detail."

katsuki stopped in his tracks, "drawings?"

turning to the walls, he effectively saw the pretty lines that adorned it "why would they waste time painting stone?"

"maybe it's part of the labyrinth," izuku shrugged. "like enigmas."

they both froze. enigmas? they grinned. it was going to be fun.

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- end of day 6 -

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[a/n]
- it took them 2 weeks to solve all the enigmas of the castle and find the exit.
- after eri, they adopted other kids (kouta, mahoro and katsuma).
- it took 6 year for the kids to build the castle. eri helped them.

- vampires age way slower than humans, that's why they were still kids when they finished the castle.
- deku was elated that the kids took after him for their pranks. he talked about it for like 160 years.
- even katsuki was a little bit impressed.

- day 7 - the birthday prank -

it had taken him three months to make it home. izuku had dropped him in the middle of the amazonian forest, leaving him there with nothing more than a good luck wish. it was vampire versus wild all over again.

that's how, three months later,

he was at their doorstep, completely exhausted, only yearning for his lover's warm embrace. even when said lover was the one who pushed him into this mess. yeah, pushed. pushed from an helicopter flying over the most unknown and dangerous parts of the forest.

smiling as he was remembering the silly memory, he kicked the door open. "i'm home," he said.

he left his shoes by the entrance, and marched to the living room. the house was plunged into obscurity, only illuminate by the light of the fireplace and of a few candles.

he was met with the sight of a table standing before him, with warm food and red wine, izuku sitting at the other side, waiting for him. the smell of his favourite curry caught his nostrils.

"oh you're still alive," izuku spoke nonchalantly, "happy birthday i guess."

"don't sound so disappointed," katsuki retorted, his heart beating fast inside his chest. "i might think you don't like me."

he got around the table and threw himself into izuku's lap.

"oh, kacchan, don't be so dramatic," izuku said, patting his hair.

"you know that i love you."

katsuki's whole body tensed. they had practically been together for their whole life, always walking by each other's side no matter what happened. they even had raised a child together, but never, ever, had they said those words.

he removed his head from izuku's lap and eyed him curiously, caging his body between the chair and his arms.

izuku was intensely looking at him, smiling softly, waiting for him.

his face softened and he smiled too.

"i love you too, izuku," he said.

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- end -

[a/n]
happy birthday kacchan! 🎉🎉