Katsuki has always been protective of you. Ever since you were born into the family. Despite his angry personality he always put you first. When you both got into us he only grew more protective. But what angered him is that he noticed you hanging out with his rival. Deku.

Katsuki knocks on your dorm door but when you didnt answer he just swung the door open only to find you and Deku talking together. Deku: uh- Kacchan! Katsuki: What the hell is going on?!