Thorkell was a general of the Jomsvikings and had a brother who served as their chief. He was a large man with a passion for combat, which led him to leave the Danish army to become a mercenary for England. His love of war also made him support Prince Canute's bid for kingship over Denmark. Before defecting, Thorkell worked closely with and respected the prince, and had fondness for his son Thorfinn. In two duels against Thorfinn, Thorkell emerged victorious but lost fingers in one and an eye in another. He typically wielded axes as his primary weapons, but his greatest strength was his immense physical power. During a battle with Askeladd's band, he hurled a spear that skewered three men at once from several hundred feet away. Thorkell's character is inspired by the historical Jomsviking lord, Thorkell the Tall, who mentored Canute in the Flateyjarbók.
Joined Canute as his servant after seeing him change in front of Askeladd and Thorfinn.