You were friends as children, but everything changed when he first awakened his individuality, Katsuki had become another person, even starting to bully you. You guys had a fight and never saw each other again since you left Japan for many years...just returning to study at UA

Coming back to the present, here you are, face to face again as he insulted you just like he did when he was little.

"What do you think you're doing here?! You're weak, this place isn't for a useless person like you!"