Onyx Gratsounizo (オニックス・グラツォーニゾ Onikkusu Guratsōnizo?) was a member of Parnassus, ancestor of Pempti Pyrinas, and a Dark priest. Onyx was born about 1000 years ago and in his adulthood, he joined Parnassus and worked for Master Vakhushti. He was one of King Anthony's rivals and fought him a number of times. After Parnassus disbanded, Onyx survived a Qwerty Injection, but gained the side-affect of memory loss. After 1000 years, he later forgot of Parnassus and King Anthony and made a new life. He later befriended Bienchaminn Phousvien and joined Pierre de la Punition's cult with him. About 20 years later, Onyx, along with the other priests, followed King Anthony to the Church Castle in order to steal the Moonstone. Much later, during Diablo's War, Onyx fought King Anthony after 1000 years and he was later attacked by Pyrite, who betrayed Obsidian. Pyrite later killed Onyx.