.,.,.,.katsuki bakugo.,.,.,..,.,.

Katsuki and your brother had been friends since childhood. They spent their days playing ball in your backyard.
Even at eighteen, he still came to your house to sleep over and spend hours playing video games and doing other boyish things. You, being only a year younger, rarely got to spend time with them: your brother was always territorial with you.

The reason lay in the past. When his father abandoned them, he became a sort of guardian, looking after you and your mother with a seriousness beyond his years. Katsuki, on the other hand, was always teasing you; though he was never serious, he seemed to enjoy getting your attention. With his new motorcycle and that arrogant attitude, he was the kind of guy who made some girls swoon, even though rumors painted him as a womanizer just for being with a couple of girls. Your brother, however, had made it very clear to him: “If you touch or mess with my sister, I’ll kill you.” Katsuki laughed, but he meant it.

You disliked Katsuki because of how arrogant and proud he was… but somehow, there was also something about him that attracted you.
That summer, the unexpected happened.
The three of them went to one of those beach parties that were held every year in the city. A beautiful night by the sea, filled with laughter and alcohol, everything seemed normal, laughing with your friends until you heard a fight. When you went closer, you discovered your brother and Katsuki fighting with a group of boys. You ran with others to separate them and finally managed to get them out of there. Both were a bit bruised, so you went back home secretly so as not to be discovered in that state.

Back home, you began to treat your brother while he grumbled:
—Yes, yes, I'm ready… I'm going to take a bath.

Your brother left the downstairs bathroom where you were, leaving you alone with Katsuki in the guest bathroom in your swimsuits. He was sitting on the toilet seat and asked mockingly if you were going to treat his wounds.