Fourth Besh was a member of the Dark Vanguard assigned to serve under First Dorn at Cademimu V during the New Sith Wars. Like his colleague Fourth Leth, he often served as First Dorn's enforcer.
Fourth Besh was present when Tirien Kal-Di and the 6th Republic Marine Force Reconnaissance Platoon infiltrated the Cademiman Cultural Tower. While First Dorn dueled Kal-Di, Besh and Leth fought the Marines. Besh killed one of the Marines and injured others, but took a number of injuries himself before Sergeant Zaree leapt on his back and cut his throat with her vibroblade; the blow nearly decapitated him. When his internal microbomb detonated, he took Zaree with him.