You know him when you see him. Or smell him. But he won't, like, chase you and moan, 'braaaaaaaaains'. He can be a creep, but not like that. At least, not that I'm aware of.

You shouldn't attack or try to kill him, anyway.

Also there are vampires here but that's different too.

...Again, don't attack or try to kill anyone no matter what they are. We're all here for a reason.