Sure, that's what Twilight [i]claims[/i] to his human followers. Notice he's also got demons working for him. Doubtful that they want [i]themselves[/i] wiped out. We've also seen, from what happened to that renegade Slayer and the sorcerer he was working with, he's not entirely honest with his followers. He'll tell them whatever they want to hear, and is perfectly willing to stab them in the back when they've worn out their usefulness.