In Zoroastrianism, the demon of avarice, gluttony, insatiability, and lust. Az is often paired with Niyaz (want) and is featured also in Zurvanite and Manichaean texts. The pair is considered supremely powerful. Az is the opponent to Atar, the fire god son of Ahura Mazda (later Ohrmadz), the creator god. In the Bundahisn text, Az swallows everything and anything to satisfy his want, but he is never fulfilled. If nothing is available, he will eat his own body. Az is not the demon of death, but he brings about death through his corruption. He is behind everything disastrous that happens to human beings. Az and Ahriman will be the last demons to be defeated by the forces of light and good.
In Zurvanite theology, Az leads the demonic hordes. In Manichaeism, Az is a female demon who is the mother of all demons and sin. She formed the human body and imprisoned the soul in it. She is Hyle, or matter and evil, and tries to make humanity forget its divine origins, thus preventing people from finding their salvation.