Katsuki Bakugou x little sister (OC)

What the heck are you doing here!

It was just a normal day in 1A's homeroom, Katsuki was getting yelled at by Iida for having his legs on the chair in front of him, but he wasn't listening, he was to busy scrolling through messages on his phone, until he came across a text from his mom.

"The old hag?" Katsuki whispered to himself thoughtfully.

"Excuse me Bakugou, but who are you calling an old hag, such foul language should not be.." Iida started

"GO DIE! I'M TRYING TO READ SEE!" Katsuki shouted back at Iida waving his phone in Iida's face violently.

Iida went rambling on about something but obviously the boy wasn't listening here is what the message said,

Oi brat, Sumi is staying at U.A now, me and your Dad decided to move to Australia since it's always been my dream the sun there is just amazing and you've grown up now, we asked Sumi if she wanted to come with us but she said and I quote, 'why are you meanies gonna leave nii-chan all alone in Japan, you can go but i'm staying with nii-chan no matter what humph' haha that brat is adorable. 

Apparently there is another little girl in U.A, not much older than her, that's the only reason they are allowing Sumi to stay on premises to become her friend, to be around someone her age. I thought that Sumi would be perfect. We are going in 3 weeks so you better get yo self home to say goodbye before then. 

BEHAVE, (sending aggressive kisses and hugs)

Katsuki's face whitened with each sentence, the thing that scared him the most was the fact that this message was sent.......exactly 3 weeks ago.

"frickfrickfrcikfrickfrickFRICK!" on the last one he jumping to his feet and smashing the table with his fist.

'Bakubro what's up, you good." Kirishima asked walking over to his hot headed friend.

"You won't underst..." he was cut off by a knock at the door. 

Normally Mr Aizawa would slither through the room in his sleeping bag so who would be knocking at their classroom door, the noise in the class immedietly dropped.

"Come in!" Iida commanded.

Itsuka Kendo poked her head inside the classroom, "h-hey sorry to interrupt but I found this kid, running around the halls screaming 'katsu-nii' so urrmm do you have any idea where she might've come from, none of our class knows.."

"Is Katsu-nii in this classroom?" a high pitched voice asked from behind Kendo.

"I don't know sweety but i'm asking..." Kendo was rudely interrupted and said child pushed past Kendo into the doorway of the class and cleared her throat.

"Ehemmm is my nii-chan here!" The child asked the whole class.

"cute!" mutters could be heard around the classroom.

"What does your nii-chan look like." Uraraka said slowly approaching the girl and crouching to her level.

"he's really REALLY tall," she stood on her tiptoes and pointed to the sky, "his eyes are red like my mama's and, and he walks like this." The kid did Bakugou's typical unnecessarily large strides.

"OI BRAT I DON"T WALK LIKE THAT!" Katsuki shouted from his seat.

"oh ye and he sounds like that." she rolled her eyes.

"Are you sure your nii-chan is in this school were are your parents." Kaminari asked not adding two pieces of evidence together.

"Wait a minute...if your class 1A and that boy was coming from that direction..." She said walking towards the direction she had heard what sounded like her brother whilst Katsuki shrunk further into his seat hoping to not be detected.