I might be able to help with ideas, but first, are all of those characters above female? Because if so, you could make it like some sort of fantasy school for female shapeshifters, witches, “gifted” spies/thieves/assassins (as in they all have some sort of interesting ability like the XMen mutant academy). Or you could just have like a co-ed school. Or maybe they’re in rival tribes in a fantasy world. You get the point, I’m a bored novelist with a lot of ideas and nothing to do.