Katsuki's New Sibling Life (boku no hero academia x child reader)

Chapter 27: Training

"So can you please tell me why does he smell like All Might?"

They minute those words left your lips, the world seemed to stop as the two nervously thought of a way to cover up such a practical fact. The man never expected you to have heightened senses since that kind of quirk is slightly rare and are mostly found in the police department.

He also didn't expect it to be accurate enough to tell the difference at such a young age.

Still waiting for an answer, you looked between the two males, who tries to avoid your gaze while thinking.

"So, your silence mean that he is..."

"He is All Might's relative!" Izuku suddenly exclaimed.

"Yeah yeah!" He nodded rapidly both sweating nervously as you hummed in thought.

"Oh! That makes sense!" You beamed hitting your fist to your palm in realization. Both boys sighed relief making sure you didn't see them before you suddenly spouted a name.

"Then you are Mister Triangle!" You chirp making the man confusingly looked at you.

"T-Triangle'?" All Might in his scrawny form questioned. You nodded in confirmation and you turned to Izuku.

"Broccoli Hero!" The boy flinched in surprise pointing at himself to make sure you got the right person. "Me..?"

"Yes! Because you saved me from that big yucky bad guy! I wanted to thank you so much, but big brother wouldn't let me..." You bashfully say.

"I didn't know Katsuki had a younger sibling..." Izuku muttered to himself trying bro remember if he recalled at least seeing you as a baby with the Bakugo family.

"I am adopted." You clarified earning an apology from the boy.

"It's fine! So what are you doing? Can I help??" You begged.

Unsure All Might wondered if it were a good idea to let a small kid help with such heavy objects. "You don't have to worry about me, see?"

Waddling over to a rundown and broken car you swiftly picked it up awing Izuku and All Might as you gave a sharp tooth grin.

"So can I help?"

[--]

"Oi, why the fuck are you all dirty?" Katsuki asked as he spotted you entering the house at sunset covered in dirt and sweat, and your tail droopy in your arms.

"I am helping at a beach clean up!" You beamed earning a praise from your mom. "Oh what a good girl you are, (Y/N)..!" She say making you cackle modestly.

"But you are still dirty so.. Katsuki, you are cleaning (Y/N) up."

"What!? What about the damn tail, can't it clean the brat!?" The said boy complained pointing at the obviously exhausted limb.

Mitsuki sent a smug look towards him resulting a groan from him, in defeat he clicked his tongue and grab you at the back of your shirt.

"Carry me properly meant!" You yelled at him grumpily.

"You stink, there is no way I am gonna hold you properly." He bluntly stated marching into the bathroom.

Without even taking your clothes off he threw you in the tub of warm water.

"Big brother!!!"

The day passed with you getting revenge on Katsuki and running away from him and by the time it was evening you both were sleeping on the couch curled you with each other in exhaustion.

"Awe look at them." Masaru lightly cooed watching you two from the door. "I never seen Katsuki act like this and despite all the active noise —it was better than him being so angry and cocky as such."

"Yeah, he finally found a force that matches his.." Mitsuki wrapped her arms around her husbands waist from behind.

"....But they still are gonna clean this mess or I am grinding them both..."

Nervously the man chuckled worried for the two in the morning.

"Oh dear.."

[--]

And just as Mitsuki declared, the two spent the first two hours cleaning up the aftermath of your revenge. Messy would be an understatement.

But it was fortunately quick despite the amount of space the mess took. And after a bath you found yourself inviting towards the door.

"And where the hell are you going?" Katsuki asked standing on the stairs like a cop who caught a burglar in the act.

Hearing him you quickly turned to him with an innocent look. "I was planning to go and meet with Tora.." You nervous as making up an excuse to leave the house.

"Don't be stupid, he called us last night saying he would go on a trip with his parents."

'Shoot' You cursed in your head finding yourself inviting towards the door.

"(Y/N)..." Just as Katsuki started to walk towards you, you washed away.

"Be back later big brother!" You yelled while you departed earning angry screeches in reply.

"Hope he won't kill me later.." You prayed making you way back to Dagoba Beach.

"Youngster, you came back.." All Might, in his original form, commented on surprise as you leapt from the ledge and landed next to him, surprisingly him.

"I did say I will help!" You told him.

"I appreciate your enthusiasms to help, but this task is also working as  training for young Midoriya.." He told you resulting to your downcast look.

"Oh.." You simply muttered as you walked to the stairs and sat down on the lowest step.

Just seeing your look made the man guilty and wanting to flip the frown upside down, but he has to prioritize his students training before the entrance exam of UA.

He was torn with his two decisions but decided to stick with the training...

"All Might, what's wrong with (Y/N)?" Midoriya whispered to the man who sighed.

"They wants to help in cleaning up but I told them that, this is for your training." The man explained.

Nodding in understanding, Midoriya looked down to the ground with a finger to his lip in thought. "How about this will also be training for you." He suggested earning a curious look from his teacher.

"You are becoming a teacher in UA next year right? So maybe.. You can get used to taking on multiple students before the actual thing."

All Might smiled at the suggestion "That just might be right." He praised earning a happy grin from the latter. "Now why don't you tell the younger the good news."

Without a moment to spare Midoriya joggers up to you.

Watching from behind All Might felt a hint of pride flourish in him as he watched Midoriya happily tell you, you can help.

'I already knew what you really wanted when you suggest that..' He thought as he sighed in amusement. 'Young Midoriya, did you warm up to the child already?'.

His thoughts were left unanswered as you punched the scrawny blonde on the shoulder in happiness. "Thank you Mr. Triangle! I promise I won't be hardheaded for you!" You gleefully say earning a chuckle from him.

"Okay! Now let's start!"

"Yay! Training Time!"

==============================
Sorry for not posting you know exams and all but I was slightly hitting a writers block so I had to recollect my plan for this book but not only that.

I was feeling tempted to actually make a fourth book when I remember saying I should take these things slow.. Aw man..

But anyway, I hope you like this chapter!

Peace!X3

-Shiki