Xero is the leader of the Hunter class creatures. Hunters were created by the ASF's Mad Scientist Qaakkex to be used to devour all living creatures on a planet of the Alien Space Federation's choosing. Xero is EXTREMELY intelligent, and was named Xero, because once he is dropped on your planet you have ZERO chance of survival or escape. Even if you manage to escape the planet Xero already has your scent and will not hesitate to travel through any and all universes in the multiverse to track you down and eat you alive. A Hunter's skin is impenetrable to every weapon in the multiverse thanks to Qaakkex and his unimaginable creativity and knowledge of biological creations and his ability to manipulate living organisms to his liking.