Xellos is a high level Mazoku (see Universe section below), who is thousands of years old. Xellos currently serves as priest and general for Beast master Zelas-Metallium. Zelas-Metallium herself is one of the 5 highest ranking Mazoku who were created by Shabranigdo, and she in turn created Xellos. Xellos temporarily served under Hell master Phibrizzo in his attempt to destroy Gaav the Demon Dragon King. Gaav stated that Xellos was given power beyond any Mazoku, leading to the fact that Xellos is above all other Mazoku, with the exception of the Shabranigdo's retainers, and of course, the Dark Lord himself. Dragons fear Xellos and see him as their mortal enemy after he killed half the population during The War of Monster Fall. In the 6th Slayers novel (Vezendi's Shadow), Xellos says his full name is Xelloss Metallium. He is also known as Beast master Xellos, "trickster priest" (by many, including himself) and "namagomi" ("raw garbage" by Filia) or simply Xellos. He is a hindrance as much as a help to Lina and her friends. He gets what he wants in the easiest way; even if it means tricking his friends, though he is not above aiding or betraying anyone as long as it furthers the goals of himself or the others of the Monster race. His trademark response to any important question is, "Sore wa himitsu desu!" (Literally: "That is a secret!" . A constant duel goes on between fans whether there is a love or hate, or even a love-hate relationship between Xellos and Filia. First appears in Slayers NEXT.