3. Atrocitus
Despite the rather evil and hellish exterior, Atrocitus was born of tragedy. The "glitch" of the robot force of the Manhunters killed all life in his sector, except himself. He witnessed his family murdered before his very eyes and from this grief came the formation of the Red Lantern Corps (emotion: rage.) His goal was the destruction of the Guardians themselves as they had created the Manhunters and therefore were responsible. His mastery of blood magic and seeing future events were interesting aspects to his character but what's so fascinating is the complete transformation into a Red Lantern from what he once was. The ring replaces his heart, the most universal of symbols relating to love. Everything he loved is gone so what need does he have for his heart any more. His rage, his desire for revenge (and ultimately for all those who have been horrifically wronged) make him a truly unique though unusual hero.