Avery Mann is alter-ego of the superhero Everyman, as written by Comic Book Guy. He's originally depicted as an overweight, somewhat dumpy deliveryman with the power of absorbing super-powers from comic books. He is portrayed by Homer Simpson.
His last name is (probably concidentally) the same as Otto's.
He appears in all episodes Everyman appears in, but H.t.W. is the only episode he appears in as himself.