peter van houten
Peter Van Houten is the author of Hazel's (and later, Augustus's) favorite book. Hazel and Augustus go to Amsterdam to meet him and have him answer some of their question about his book, An Imperial Affliction, but he turns out to be a total douche. Once he finds out about Augustus's death (by looking at the Indianapolis obituaries) he goes to Augustus's funeral and apologizes to Hazel about how he acted. This shows that Van Houten was a dynamic character in the story, as he did change his attitude to Hazel and Augustus. However, little is none about Van Houten's history other than he is the author of that book, is a drunkard, and lost his 6 year old daughter to leukemia years back, which would make him a flat character.