Xev was born as Zev Bellringer in the planet called B3K, in the Light Universe. Her parents abandoned her and she was raised in the Wife Bank where she was taught all necessary information that a good wife needed to know. But Zev didn't quite please her husband-to-be, but instead punched him in the face. This led her to Cluster, the capital planet, to receive a punishment for failuring her wifely duties. Her punishment was to transform her into a loveslave, but that neither went fine.
During the process, as a result of many strange coincidents, a cluster lizard made its way to the room to mix things up even more. It did die, but some of its blood got mixed together with Zev's, giving her some cluster lizard DNA. Cluster lizard destroyed the body of the robot 790, who was in command, leaving only a head behind. After Zev's body had been transformed (all loveslaves were designed to be the most beautiful women in the universe), she was able to free herself before having the brain job done which would have basically taken away all her independent thinking. Instead, Zev gave this treatment to 790 robothead.
Zev joined Stanley H. Tweedle, Kai - last of the Brunnen-G, and the robothead 790 (who was now totally in love with her) and they experienced adventures together while cruising the universe with their big living spaceship, Lexx. However, Zev's life came to an end on a MedSat medical terminal when she was saving Kai. Stanley and Kai took Zev back to the Lexx, that is, the yellow goo that was left of her in addition to the black rubber piece of clothing and stored it in a jar.
Next, Stanley and Kai received an interesting visitor, a plant who calls herself Lyekka. She had a bad habit of eating people, but none of the crew could blame her, because it was Lyekka who brought Xev back to life. Even though Lyekka used Zev's proteine (the yellow goo thing), she wasn't able to make an exact copy, because she had to rely on descriptions that she had read from Stanley's and 790's minds. But in the end, no one could care less, because despite the new look, she was truly Xev inside, obtaining all the memories of her life as Zev.
Xev being a loveslave gives her a very active libido and she is getting really desperate for not having anyone to have sex with. Xev loves Kai, but Kai has been dead for over 2000 years so he has no desires at all. The other male companion on the Lexx, Stanley, makes Xev feeling sick and the thought of having sex with him is absolutely impossible. And 790.. well, he is just a head.