During World War II, Thunderfist was a member of the Crusaders. Together, the Crusaders fought on behalf of Britain. Unknown to any of the team, Alfie, their benefactor, was really a Nazi double-agent sent to create trouble both for the Allied forces and the Invaders.
When Alfie's deception was discovered, Mason got rid of his gloves and retired from crime fighting. His whereabouts after retirement are unknown.
A large man, Thunderfist used a pair of gloves to give him enhanced strength.