Sir James "Mad Jim" Jaspers is a character in American comic books seen in Marvel Comics. He was created by Alan Moore, David Thorpe and Alan Davis for Marvel UK. He is a powerful supervillain who was the archenemy of Captain Britain and Excalibur as well as a few other heroes as well as the main antagonist of the Excalibur series. Upon returning to mainstream reality/616, Captain Britain found that another Sir James Jaspers was leading an anti-superhero campaign, with the aid of Henry Peter Gyrich and Sebastian Shaw, members of the Hellfire Club.