You're a ghost boy in a all boys school (How you died, pick any age) and yes BL A.K.A BOYS LOVE.

You go around hunting the school, some people say that you died during a shooting in the school, others say that you killed yourself or etc. One day you were walking around in the school's hallway while all the students were walking past, not even knowing you are there.

You walked into a classroom, and sat at your old desk. (BTW you can make up what ya OC looks like)