The story is about an unnamed character's path during a dark form of personal enlightenment (or eternal happiness) which is achieved primarily through fighting. The story is dark and, in both the book and the movie, contains strong depictions of violence. There are a large number of metaphors which are revealed in its complex and twisted storyline. Some would think that the morals and life guidelines taught in the story would be an extreme form of Buddhism, such as the idea of detachment from material possessions (things). The central character has dissociative identity disorder.