Evil is a common theme in literature; it is especially common in gothic literature, such as The Scarlet Letter by Nathaniel Hawthorne and Moby Dick by Herman Melville. Roger Chillingworth, the evil character in The Scarlet Letter, is evil because of his desire for revenge against a man with whom his wife cheated. Captain Ahab, the evil character in Moby Dick, is evil because of his need to obtain revenge for the loss of his limb. Evil, chiefly in these novels, causes most of the characters’ struggles. Evil manifests itself similarly between Captain Ahab and Roger Chillingworth. Roger Chillingworth is a physician whose evil is deeply rooted in revenge; his desire to obtain and enact revenge causes him to become mad and eventually perish.