Werewolves are an elite class in The World.
A hidden class only available through the "Class Change" system to Knuckle Masters who obtain a certain item, the Werewolf class allows its user to transform from their original class into a wolf form, and vice versa.
Now any type of class can become this secondary class if they do the event.
(If you want to be this let me know in your post and I'll say yes more often the less people I have as a werewolf)
(Info from .hack//wikia)