Werewolves

The legend of the werewolf as we know it today is said to have arisen in Europe in the 1500s, but the idea of men transforming into wolves (and other creatures) goes back to the dawn of human history. In recent times, the werewolf seems to be being rehabilitated into a "good guy", someone for whom we feel pity and admiration. Think of Oz in Buffy the Vampire Slayer, Professor Lupin in the Harry Potter books, and Angua in Terry Pratchett's Diskworld books.