I think Anne Rice is a Christian? So, although her books are dealing with vampires, there may be a Christian morality to them. In LOTR, there are wizards and goblins- all sorts of mythological creatures, yet the Christian ethic is there. The same is true with the Narnia series- The Lion, the Witch and the Wardrobe is clearly Christian allegory- yet there are satyrs and centaurs, witches and dwarves.