Prince first appeared on the season premier of the third series, when he and some of his cohorts board the Lexx as it passes through the atmosphere of Fire. Soon, the crew is split up and Prince takes a certain fancy to Xev, asking her to be his "Queen." She refuses, but he doesn't stop there.
Near the end of Season Three, he judges Stanley after he dies. When Prince deems Stanley material for Planet Fire, Stan's soul is sent into a purgatory-like state, showing more evidence that Prince is a spiritual entity. Also, Prince can die physically and come back as any form he wishes to. He used that tactic to reincarnate as a living Kai (he's dead, remember?), only he tried to kill Stan so he was exposed.
He takes pride in "being very good with pain."
When the crew all managed to get back onboard the Lexx, Xev (Stan died, so the key went to her) blows Fire up. In retaliation, the essence of Prince (different from the essence of His Divine Shadow) blows up Water, and after a scene with a myriad of ghosts, Prince's essence is seen descending on the west coast of North America.
Prince reappears in the Fourth Series as the director of the ATF and de facto ruler of the United States. The new president, Reginald J. Priest, was one of Prince's primary lackeys back on Fire. From there, he doggedly pursues the crew of the Lexx as they try to escape him.
Prince is played by Nigel Bennet