Xev is the reincarnation of Zev. At the beginning of LEXX - The Dark Zone season two, Zev, the original love slave-cluster lizard, takes an energy beam meant for Kai the dead Brunnen G assassin and dies.
Fortunately for fans of the show and the continued frustration of Stanley Tweedle, Zev is reincarnated as Xev by Lyekka, a carnivorous plant in the form of a girl from Stanley's dreams, using protein Lyekka got from eating some astronauts.
The new Xev is more worldly, more animalistic and saucier than the original Zev. She has all of Zev's past experiences and maintains Zev's desire for Kai and distaste for Stan. She is more exotic in appearance than the conventionally pretty Zev and wears an even sexier cluster-lizard outfit.