The leader of a New York street gang, Brock Rumlow was recruited into Taskmaster’s school for criminals, where he eventually became a teacher. During a mercenary mission, Rumlow met the Red Skull and decided to work with him, taking the codename Crossbones. As the leader of the Red Skull’s hit squad, the Skeleton Crew, Crossbones has fought with Captain America on several occasions.
Crossbones is a world-class hand-to-hand fighter. He is an expert pilot and a marksman with crossbows, guns, and throwing knives. His weaponry includes firearms, a collapsible crossbow, a wrist spike, wrist-mounted spring-loaded stilettos, various explosives and poisoned knives.