Guess what? We've got another narrator for you. Mr. Compson is Quentin's father and General Compson's son: he's basically the link between the real story and the weird guessing-game version we have as readers.
Like each of the other narrators, Mr. Compson has his own take on things: his version of events tends to paint Sutpen as a tragic character. He considers everything in terms of big, abstract themes, as if everyone is an actor in some classical tragedy. In fact, one of Mr. Compson's guiding beliefs is that man is controlled by fate.
Unlike the demon Miss Rosa depicts, Compson sees Sutpen as a hero – a very Southern hero, at that – driven toward destiny but doomed to destruction. But can we trust this guy? After all, he has not had any direct contact with Sutpen (which Rosa most definitely has). His information comes mostly from his father. How many degrees of separation before things start to get fuzzy?
And one last thing: if you read Quentin's "Character Analysis," you'll remember we suggested that Quentin might be kind of like us, the readers, trying to unravel a complex mystery. If that is the case, isn't Mr. Compson kind of like our author, William Faulkner? It makes us wonder with which narrator Faulkner most associated himself: is he more of a Compson or a Rosa? A Quentin or a Shreve? What do you think?