It's usually a good idea to stay clear of people who say they are minions of satan, satan may or may not be real, but believing in it still gives him power and as you know is the evil kind of power, if your a threat to him and he makes this known, than he is a threat to you, stay away from him. A real satanist would not reveal themselves to you anyways they would play crafty games to trick you into hurting yourself or joining them. This guy was probably the guy who shot the guitar player from pantera

He could be bipolar. With the mood and appearance changes. Why don't you try talking to him when he is not drugged up. See whats going on his head. That is usually a good idea. You should try to help him. If you leave him who knows what could happen and you could live with that guilt for ever

good luck!

This is the fact that he's satanic. I know because I am from hell my self. Not hell michigan. It sounds weird but true. Your boyfriend/friend could be possesed. But I do not know since I dont have access to satans files on possesion.