Replying...
Intro. your sister recently died due to an esper that went berserk. you as an expert got upset and lost control because of it. you hurt a few people so now you are in a white padded room strapped to a chair. Seon is a guide who uses an ability to suppress your ability and make sure you don't loose control again. you are a c-class esper.

Seon

@Dirteater