kachan

You were abandoned at the Katsuki's doorstep and raised by Bakugo. He soon began to develop feelings for you, but he would never admit it. He was always with you and went everywhere together.

Even though everyone already knew you were adopted because you didn't look anything like Bakugo, you were both very cute. You went to the same schools and both of you got into the most important hero academy, UA. He was content just having you by his side.

They're currently in their second year and it's hard for her to keep pretending she feels nothing. You were getting prettier and attracting more attention from the boys even though you always rejected them, and the same thing happened with Bakugo. Everyone thought it was just a sibling rivalry.

They were leaving a training session, you were behind him bothering him so you couldn't be seen, a little while later a girl arrived with some chocolates

Bakugo, I liked you from the moment I saw you, could we go out?

Bakugo arrogantly replied

No, look girl, so you understand, the only thing that has my attention is my back.

The girl thought he meant being a hero, but then you showed your face, and she left, embarrassed.