Rhyxali, the Queen of Shadows, is the demon princess daughter of Pale Night (the Mother of Demons). This in turn made her the sister of Graz'zt (the Dark Prince), Vucarik (Consort of Chains), and Zivorgian, the Lady of Ripe Carrion. Rhyxali was a long-standing ally of Graz'zt. Rumors said the two were working to absorb a Material Plane world into the Abyss, trapping it in the parched realm of the Nerebdian Vast, the 48th layer of the Abyss. Rhyxali's realm of Shaddonon existed on the 49th layer of the Abyss.

Rhyxali's rule extended over shadow demons. Unlike her contemporaries, Rhyxali seemed content to rule Shaddonon without the desire to acquire a larger realm. Personal power in the form of information and secrets was the only thing Rhyxali coveted. To this end, Rhyxali created a vast library of secrets run by her lieutenant, Viractuth, a marilith sorcerer. The library's contents were so disorganized and chaotic that only Viractuth could find anything of relevance. Virtually all demon lords called Rhyxali an ally and sent envoys to deal in secrets.

Her true form was that of a tall humanoid woman with jet-black skin, although she regularly appeared in an incorporeal shadow-form. Her symbol was a jet-black dagger. Rhyxali delighted in killing and preferred to strike unseen. Rarely did she show any interest in the Material Plane or mortal worshipers. A large shadow demon named Kadasha served Rhyxali as a bodyguard and accompanied her on hunts in Shaddonon's twilight. Rhyxali did not ask much from her other minions, except that they watch and report back what they learned as they freely roamed the Abyss.