Xelloss (Japanese: ゼロス Romaji: Zerosu) is a mazoku and the priest of Greater Beast Zelas Metallium in the Slayers series. Xelloss was created by Zelas during the Kōma War, which took place approximately 1013 years before Slayers TRY. Unlike other subordinates of mazoku lords, Xelloss is the sole immediate servant of Zelas Metallium, and thus a great deal of her power went into his creation. Because of this, Xelloss is the most powerful of all the priests and generals of Ruby Eye Shabranigdu's subordinates.