Risor was one of Quendril's assistants. He was a failed experiment to create the perfect warrior. He wanted to warn Veltreena that Zaadur hated her as he was in love Veltreena.
When Zaadur murdered Veltreena, Risor wanted revenge. When Zaadur planned to conquer Earth with the Ice Warriors. She launched a rocket, which Risor stowed away on. Risor then blew the rocket up, killing himself, Zaadur and the Warriors, gaining his revenge. (AUDIO: Lords of the Red Planet)