Sir Raven, voiced by Julian Stone, is a big raven in a somewhat rich getup. He is seen in a stereotypical Victorian living room, complete with a warm fireplace and a cushioned arm chair.
He randomly appears in some episodes and narrates part or the whole story of the episode, similar to Masterpiece Theater. He has an odd tendency to screech repetitions of the last word he said, and holds a great deal of contempt for everybody.
It also seems that he has the ability to shoot cheese from his armpits (which is confirmed in the episode "Billy and Mandy Moon the Moon").