Mattias is the adoptive son of Xu Wenwu who was later trained to become an assassin for the Ten Rings and was given a retractable blade on his right arm, gaining him the name Razor Fist. Mattias was sent by Wenwu to retrieve his son, Xu Shang-Chi, and later tracked him to the Golden Daggers Club. Mattias participated in the Battle of Ta Lo on the side of the Ten Rings, but later agreed to side with the Ta Lo warriors help defeat the forces of the Dweller-in-Darkness. After the battle and Wenwu's death, Mattias continued to serve the Ten Rings under Xu Xialing's rule.