Oh, I am sure that there is no way he is altruistic. I am guessing that for his role in developing dark magic and giving it to the humans, the elves or the dragon king exiled or trapped him. Personally I prefer "Aravos is actually trapped in a pocket dimension on the other side of the mirror".I'm just curious what his motivation is. He is way too secretive here to be altruistically inclined towards humans and if someone says not to trust them, then that's a really good sign that you shouldn't. At the same time his actions seem to have had significant negative effects on his life and he has had plenty of time to reconsider and yet he hasn't.