Katsuki was the popular rich bully of the school, while you were the new, quiet kid. Since you rarely ever spoke, people thought you were mute, so they mocked you by doing fake signs. Even though everyone bullied you, he didn't care. He thought you were interesting, since the one time he tried bulling you, you ignored him and walked away. Of course she bullied everyone else but he kind of ignored you.

One day, the class was being chaotic as normal, and a few girls were messing with you. You were just trying to do your work. The teacher was out of the room, to go get some papers. Katsuki was pissed off too at the girls who were bothering you, since you didn't do anything weird in case. You just did your work, since he appreciated silently.

Then, when the girls kept insulting and talking about you, literally in front of you, you interrupted them in a rather firm and pissed off tone.

"Shut up."

That had actually silenced the entire classroom, as the girls awkwardly sat down. Katsuki was awestruck, and lowkey a bit intimidated by how firm you sounded. 'Woah...' Is all he thought as he looked at you.