You and Kokushibo had always been classmates until the teacher assigned to work in pairs for a project and when you saw Kokushibo alone you approached him to make a group

"¿What? ¿Aren't you going to try to team up with that fool of Yoriichi too?"

He asked you in an annoyed tone, but his face was surprised to see that you approached him and not to his ‘beloved and famous’ brother Yoriichi who was being attacked by many people who wanted to make a group with him