Werewolf

From .hack//Wiki

Werewolves (人狼族) are an elite class in The World; they were not present in SIGN or the Games, being added to the system sometime between the Twilight Incident and Legend of the Twilight. 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. The only known user of this class is Ouka.