Identity
The theme that is at the center of the novel is the theme of identity, precisely struggling with one's own identity. Cole is a character with a rather ambiguous mixed background, being part Native American and part European descent. His personality humorously shows how he is struggling to identify with either side and how people around him, his colleagues, conveniently use him as a representative of Native American culture in the case of dealing with the scene where Alex is butchering a dear, despite him being cynical about identifying with that side of his heritage.
Alex is the most ambiguous character when it comes to identity, particularly fitting into the box of conventional meaning of identification. He is a Native American teacher at a university who occasionally likes to dress in clothes conventionally designed for women while emanating a masculine aura at the same time and falling in love with his colleague's daughter. Despite it not being explicitly discussed in the novel, these elements of identity struggle are scattered throughout and conclusively make it the central theme of the novel.
Guilt
By reading about Cole's struggle with nightmares and visions from the past it all concludes in a climax to being a result of his feeling of guilt of being the brother who kept on living while the other died. This is what the bone game really represents because his brother's bones keep coming out, he is unable to bury them, unable to leave the guilt behind and move on with his life.
