Hi!! I absolutely love your stories! I was wondering if you could write a story about Bakugou having a younger sister (like 12 yo or something) and she gets to tag along with her brother for the day. However, she thinks he's "old and lame" and says stuff like that to him, but she talks about how cool everyone else is. And say someone like monoma makes her cry, and bakugou just immediately swoops in to protect her, and he becomes her hero.
Sorry for the lengthy request!
A/n: I am soooo bad at writing. It's actually insane, hopefully itâs good enough though!Â
Cw:Fem reader, reader is 12 and adopted, also hinted at having bad foster homes previously, and is a bit of social butterfly, hurt to comfort fluff at the very end, OOC bakugou, minor swearing
It really all started when Bakugou's mom and dad realized that they hadn't gone out for a vacation in a while. One of their kids was busy getting settled into his dorm, the other, far smaller, far nicer one, was just easing back into school after summer break. add the fact that both of them were quite busy at work, then it became apparent that they had been neglecting their lovely little relationship.
Of course, it seems natural that they would go out, perhaps to a little resort in the countryside, where they could relax in nature and decompress together. It seemed nice, for the two of them.
There was one problem however, Little old Y/n. Sweet Little Y/n, their adopted daughter. She was, what one may call, a bit of a cry baby, like her father in that way, she never did like being away from family for too long, not that she'd ever truly admit it, having been neglected by her previous "families".
Thankfully, they had one last family member that could stay with her so that Misuki and Masaru could go on vacation like they wanted to; Katsuki Bakugou. Â
That's why they were here now, they had packed up everything for a comfortable weekend at the UA dorms all into two neat bags, Masaru handed one over to Y/n.
"listen, I now your older brother can be a little bit of a sour puss, but I promise you, that he does care. so- can you be good kiddo?" he said.
and with a look that held no true malice, she groaned out a "FINNEEE."
she said just as Bakugou showed up on the front porch to pick her up. This time, it was Mitsuki that talked. "Katsuki, I swear to God, if this kid doesn't come back in one piece I'm going to break your arm, GOT THAT?!"
"Whatever you old Hag! just run off already."
"WHAT DID YOU JUsT CALL ME!!?"
You know, a normal conversation in their household, while Masaru and (Y/n) stand off to the side, not willing to possibly get hurt in the crossfire.
It wasn't too long before the Bakugou parents said goodbye to their children and drove away in their car, excited for a vacation. Besides, it should be fine, they were only going away for a weekend anyways, and Bakugou was training to become a hero! He lived with heroes too!
They should be fine. With that, they left little Y/n and the big scary Kasuki, alone.
-well, not entirely alone-Â
"Hey bakubro! where those your parents that you were talking to- oh, hey!" Kirishima said as he carried his bowl of cereal out onto the porch.
"Who's this little lady?" The red haired boy crouched down to her level to look her in the eye to greet her. He smiled, a sharp, toothy, sweet smile
"My adopted sister" Bakugou hissed out, he took her other bag in his arm, "c'mon, Y/n, lemme show you my dorm so you don't get lost." He expected that Y/n would follow him, and that he would show her his room and let her play games on his phone for the majority of the day while he caught up on homework.
Y/n after all, was a pretty nice kid, he doesn't remember her making too much of a fuss during their time together as siblings. But just because that's what was expected does not mean that that's what happened.
"Hi! I'm Y/n, who are you?"
"I'm Kirishima! I'm one fo Bakubro's friends."
"Oh, you're spiky hair, Katsuki talks about you when he comes over."
"Yeah, that would be me alright, manliest guy around!"
Their chatter was lost on Bakugou, as he watched one of his best friends have more conversation with his sister than he had in the past year at the dorms.
It was an odd sight, Bakugou never had truly been one to have a close relationship with his sister, nor have talked to her too much.
And the more he saw her chatting with Kirishima, and then, when they went inside to meet the rest of his friends, the weirder it seemed to him. Next thing you know, sheâs talking with pink cheeks and Yayorozu about fashion. Then with Sero about some random movie she saw last week. And somehow she got to Aizawa Sensei, Â and was talking with him about cats.
What could Bakugou do? He promised himself that he wouldnât lose his temper, not in front of Y/n anyway. Who knew that she was this social? Hell, heâs pretty sure sheâs talked with mere strangers in one day more than heâs spoken to her ever.
But what can he do? tell her to stop talking with others and to shut up? Well, he could, but it probably wouldnât fly well with his mom.
Thatâs how most of the day went, Bakugou would bring her along on whatever chores and errands and everything that he had to do that day, and she would talk non-stop with everyone she met to along the way.
Bakugou tried his hardest not to start yelling. I mean, itâs just weird, isnât it? How come she likes literally everyone else more than she likes him? Heâs supposed to be her older brother, what kind of a sister doesnât even spare him more than a glance on one of the few days that theyâve truly had together? A bad one, to him, but one he sort of loves nevertheless.
So he stays quiet, until he finally manages to get some time alone with her in his dorm. Finally, he can catch up with her. No one to bother them, just pure brother-sister bonding time as mom would have called it.
At 7 pm, he sat her down at his desk while he brought out some fluffy pillows and blankets. He even bought her favorite movie on his laptop for her, they could watch it together. He never did like the movie, but itâs only a couple hours of pain followed by a very happy sister. She used to love it when she was younger.
 In an attempt to strike up a conversation he started with âSo⌠Y/n, howâs school going?â
âWell⌠are you having trouble with classes or people or anything?â
âNo, Iâm- Iâm okayâ
It was at this given moment, Bakugou was really wondering if itâd be easier if he just told mom and dad to leave her at grandmaâs house.
â...Your friends are really nice.â She started this time.
âYeah! Kiri and Todoroki especially! I also really liked talking with Deku again, itâs been a long time since Iâve seen him. Heâs still a nerd but a much stronger and cooler one, you know? and - and Kaminari, he can power up cellphones and electronics and stuff with his quirk! Isnât that cool? I canât believe you get to hang out with these guys all day, theyâre awesome.â
âYeah, well, what about me..?â
With a laugh and smile she said âyou? no offense katsuki, but youâre kinda lame compared to these guys.â
âYeah, youâre all old now, you're not that much fun anymore. Besides, you never come by the house anymore- what, what are you doing? Kasuki!â
Bakugou by now had started pushing the poor girl out of his dorm and towards the door. âKicking an ungrateful brat out of my room thatâs what!â
âWhat the hell! Why are you acting like this?â
âYou know why! Now out!â
âOut!â and with that, Bakugou shut the door of his room in his sisterâs face, leaving her to strom out the hall, and eventually, out of the building.
Instead of waiting around in the hallway, she opted to sit outside on the porch. Sometime along the way, when she didnât even notice, she started to cry. No one bothered to follow her, too busy stuck in their own worlds.
And itâs like this that little Y/n found herself crying on the steps to the UA dorms all alone. She hated- hated being alone.
It was like this for a little while, her sniffling into her hands, occasionally mumbling a âStupid Katsuki, stupid mom, stupid dad.â mainly stupid Katsuki.
That is- until a figure sauntered up the street. UA workout uniform, water bottle and duffle bag in hand. She couldnât see the face. As the figure approached a lamp that illuminated his face, his blonde hair simply glimmered.
Though, he didnât appear to be anyone youâve met yet, maybe he was from class 1B? Whatâs the point anyways,not like he's gonna help. And help he didnât.
âYou there! Little girl, why are you crying? Did somebody take your blanket or something.â He yelled out.
âOh leave me alone! Iâm not little, it's none of your business!â
âOh hell no!, why are you outside the UA dorms, weak little things like you donât belong here anyways, outside the 1A dorms too, donâ t you know that those losers simply canât do anything right?-" The stranger just kept ballbering, and blabbering tends not to be one of those things that help when youâre crying.
In fact, in Y/nâs case, it just made it worse, and worse, and worse. Her eyes were red by the end of it. Again, the stranger would just not stop blabbering!
At least that is until âOi Monoma, the hell you doinâ here? And what are you doing with my damn sister!?â
âBakuogu? Sister? Hah! So thatâs why sheâs crying, sheâs sad sheâs related to a weakling like you!â
âWhy you little-!â and with that, all it took was an explosion powered punch to the stomach to get rid of him.
âAh! What the hell! Fuck, this isnât over!â
âYeah! Yeah! just go, and get the hell away from my sister you asshole!â With that, Monoma scampered off, probably to snitch to a teacher.
Bakugou turned back to Y/n. âAre you okay?â she shook her head no.
âListenâ he started, sitting down next to her on the steps, âIâm really sorry- it was a dick move of me to get so mad at you, sâjust that I barely see you these days, was hoping we could talk and chill like we used to. But youâre all grown now- and- it just feels like you donât need me anymore.â
âYeah, Iâm sorry.â he finished.
Y/n wiped at her tears, Bakugou stopped her though.âHere- lemme um, get that fâyou.â
he brought out a tissue from his pocket and wiped them away for her, one hand tilting her cheek up, the other dabbing at her cheeks gently. It was like this that âSuddenly!
Suddenly, He found himself wrapped up in a hug, tight one, one where she cried into his neck for a good 2 minutes
âIâm sorry too Kats! Itâs been so long since Iâve seen you and it feels like I donât know you- and- and- itâs like you hate me so I guess that you donât-" most of her words were lost on him, between sobs and sniffles that all he could really figure out.
"Hey, Hey! Kid, slow down. One thing at a time, how about that. An apology acceptedâŚ
I guess we both fucked up.â
This time, she nodded yes into his now tear stained shirt. Bakugou let out a sigh. âHow about we- um, watch a movie, and eat some food first, then we talk? Does that sound good? Yeah, let's go inside."
And really, thatâs what they did, watched a movie and ate some food- andâtalked. As siblings tend to do. And while it may not have been easy nor fun, it was to mend, and to help, and to hopefully, teach.Â
Monoma: âIâm telling you Vlad sensei! Bakugou is a danger to the student body!â
Vlad King: âWell then you probably shouldn't have gone around mocking his sister MONOMA.â