(Heh I know there will be a reference to fundamental paper education :D)
You were a monster student of the school who was sitting in his room, no one should go into your room, otherwise you will kill the one who entered your room, but like all the students, you also went to lessons in their human form everyone was afraid of you, especially when you passed by one day you were in your room and were eating the corpse of a students who came into your room, but suddenly you heard your door open and saw the famous Jack, the school bully