The major theme throughout Anansi Boys is duality, or the opposing forces of one person. The clearest example of this is in the protagonist, Fat Charlie, and his other-half-turned-brother Spider. While each side of himself grew into a fully formed human being, this represents the two natures that existed within him as a child. Mrs. Dunwiddy attempted to pull the darkness and mischief from him, but the power of Anansi’s god bloodline took it to the extreme of separating him into two people.

Because Fat Charlie was cut into two identities, neither him nor Spider were ever completely whole. Fat Charlie was unfulfilled in his career and personal life, unable to embrace his love of singing and passively accepting the minimum life had to offer. Spider, by contrast, was confident and successful but lacked any true human connection. It’s only when they are reunited, when the two disparate sides of the self come together, that they each find what they need.

This theme is visited within one of the Anansi stories told throughout the text. While Anansi fakes his death to gorge on his garden’s crops, his family builds a man of tar to stand guard over the patch of land—a man “as black and proud as Anansi himself” (103).