SMACK.

That was the second slap Katsuki saw which hit you. What the hell was happening to his sister..? Mitsuki had sent Katsuki to pick you up from school, but now he's witnessing you getting bullied from a specific guy, the faint voices of you saying "I'm gonna be like my brother!" "Katsuki isn't weak!" and other stuff about Katsuki.

Connecting the dots, he realized you were getting picked on by a kid about how you're weak and how Katsuki is so much better than you. Clenching his fists, Katsuki couldn't stand it anymore. Now storming towards the kid with eyes that could kill.

"Oi! You. You fucking bastard!"

Katsuki yelled out, capturing both, you and your bully's attention as both of you stared at him wide eyed, clearly not expecting him to come here.