Silver Fist was a fictional super-villain who did battle with Norman Power's White Knight persona. He had originally been a Cyberman who became trapped in the Land of Fiction. Jason, as Master of the Land, gave him a domino mask and a cape and just "let him get on with it."
One evening he tracked the White Knight to his cave in New York City and attacked him. The White Knight used a gun he had taken from the Glitterbug that fired gold energy and used it to kill Silver Fist. He was devastated until he saw Fist was only a robot of some kind. (PROSE: Conundrum)