AHRIMAN, the name of the principle of evil in the dualistic doctrine of Zoroaster (Gr.'ApEiµavLos in Aristotle, or 'Apecyavns in Agathias; in the Avesta, Angro Mainyush)—"the Destructive Spirit") . In the Avesta he is called the twin-brother of the Holy Spirits, and contrasted either with the Holy Spirit of Ormazd or with Ormazd himself. He is the all-destroying Satan, the source of all evil in the world. Eventually, in the great world catastrophe, he will be defeated by Ormazd and disappear. (See ZOROASTER.)