We know from the book they are three main groups: human, werewolf and  vampire. And sub divisions of those groups are hybrids, shapeshifters, and in vampires: the Volturi and so called, Vegetarian vampires, such as the Cullens. But, we hardly know anything about true werewolves ("children of the moon") except that the Volturi are attempting to destroy them in genocide hunts after one almost oblit…