What is the theme in Anansi Boys: A Novel by Neil Gaiman?

One major theme in the novel, Anansi Boys, is the battle between good and evil. The story is interwoven with numerous examples of good or innocence, winning out over evil. One example is in romantic relationships involving Fat Charlie and his brother Spider. A somewhat shy and unassertive youth, Fat Charlie worships his fiancée Rosie and play along with her game of no sex before marriage. Then Spider appears on the scene and promptly starts sleeping with Rosie, breaking his brother's heart and revealing Rosie as somewhat of a phoney. But by the end of the story Fat Charlie has married Daisy, the cop, and is raising a son. The reader senses that this is a better match for Fat Charlie and that his goodness and honesty have amply rewarded him.