Could JK Rowling's favorite character be a bad guy? Strange as it may seem, there is compelling evidence that Lupin is not what he appears to be. A trail of clues, hints and wordplay leads through all five books, from Harry's first suspicion that a werewolf might be killing the unicorns to the murder of Sirius Black. Readers may find it difficult to believe that Rowling could call a character who betrayed his dearest friends her favorite, but if it is her purpose to show that the potential for evil exists in all of us, not just in a special class of people called villains, she must show us how a genuinely good person, one whom she would like to meet in real life, could succumb to evil.