Revenge Season 1. Since the show's protagonists are anti-hero's or even villain protagonists, the main cast qualifies. Most of the members however, are unaware of Emily's scheming and their roles in the plots, leading to some delicious dramatic irony.
The Mentor: Wilson Loewen, until he turns his back on Vern.
Bigger Bad / The Man Behind the Man: The actual leader of the national Aryan Brotherhood, whom Schillinger communicates with in one episode and clearly takes orders from, but is unnamed and merely exists to prove that the Oz faction of the Aryans is merely one chapter out of a national brotherhood.