William "Bill" Williamson is a central character and one of the primary enemies in Red Dead Revolver 3dn edition and Red Dead Redemption Part I The American West and Part II The Mexican Revolution. He is a former gang partner of John Marston. Marston has been extorted into hunting down his former brothers in arms, with Bill Williamson being the primary target. The hunt for Bill Williamson has taken more than half of the game plot, and is the central motivating factor throughout.