If I ever included something like werewolves I'd use it as an attachment to the world and as a little patch intersecting other patches presenting that world's range of creatures interacting with the ch's I'm focusing on, I like what Rowling did by giving about fifteen pages worth of content relating to werewolves in Potter, you had a great idea of how werewolves fit into every facet of the wizarding world without really knowing a massive amount about them. I don't like werewolves that much but I like the transformation of humans into something bestial and feral, many creatures or concepts can lend themselves to the same kinda shape.