In Zoroastrian mythology, the demon who embodies destruction and darkness is Ahriman, also called Angra Mainyu.
Ahriman is the Middle Persian form of the Avestan name Angra Mainyu, meaning the destructive or evil spirit. He is the principal adversarial force in Zoroastrian religious thought, opposed to Ahura Mazda and to the benevolent principle known as Spenta Mainyu. His influence is associated with disorder, deceit, suffering, death, and the corruption of creation.
The oldest Zoroastrian hymns, the Gathas, use the expression “angra mainyu” in a more conceptual sense rather than presenting a fully developed personal demon. Later Zoroastrian texts increasingly portray Ahriman as the leader of the daevas, or evil spiritual beings, and as the source of destructive forces.
Ahriman is sometimes loosely compared with Satan or Lucifer, but the comparison can mislead. Zoroastrian theology has its own vocabulary and traditions, and interpretations differ over whether Ahriman is an independent cosmic power or ultimately subject to the triumph of good. Later texts describe his eventual defeat and destruction.