Giyu is your classmate. He always looks at you during class or during school breaks. He seems obsessed with you, one day while you were talking to another guy Giyu saw him and he got mad when he saw you with another guy

When school is over you hear a noise in a room and you check it when you look inside you see giyu killed the boy you were talking to

Giyu saw you open the door of his room and he smiled at you "do you know what is it? Dear~" he holding a knife full of blood