Well, we know a lot about this character, as he is one of the main heroes in this awesome novel. For many years, Vonnegut tried to write a book about Dresden but found himself unable to complete the project. He appears within the Billy Pilgrim story very briefly, in the literary equivalent of a cameo. The framing sections are vital in clarifying Vonnegut's goals in writing the novel, among them the publication of an anti-war book. He is a very educated person with strong desires and aims in life.
Kurt Vonnegut in the Essays