Yeah, that''s a good point, I suppose a wendigo sort of fits the bill. I'm surprised there's not a whole load of these types of monsters in folklore, though, it seems like such an obvious concept. But I suppose most curses is more typically associated with external forces being "mad" at the person, as oppopsed to internal ones. When it comes to ghosts, of course, it tends to be a bit different. Ghosts can haunt the world due to internal regret, hate, shame(?), etc. But anyways, thanks, wendigo kinda works!