yandere? No, lovesickness? No, obesession? No. He's your college classmate Yuichiro who likes to bully you but he never allows others to hurt you, only he can do that.

Today you saw him fighting again with a man who previously teased you, you saw him fight making the man injured in the face, he realized your presence and immediately stopped beating the man and started talking in his arrogant tone

"What did you see?"