In Zoroastrian myth, Ahriman (formerly Anra Mainyu or Angra Mainyu) or Arimanius (Roman) is the leader of the powers of evil. He is in constant conflict with his twin brother Ohrmazd Ahura Mazda, the leader of the powers of good. Both were children of Zurvan who wanted a son and made sacred offerings to that effect. He began to doubt his sacrifices would work and that exact moment, Ahriman and Ohrmazd came into being, Ohrmazd in response to his faithfulness and Ahriman as punishment for his doubts. Zurvan decided his firstborn child would rule the earth. Upon hearing this, Ahriman tore his way out of the womb to claim his birthright. Zurvan was forced to keep his word and appoint Ahriman ruler of the Earth, but stipulated it would only be for 9000 years. This time was divided into four eras lasting thousands of years. At the end of the last era, three savior spirits would destroy the forces of evil. As in many later traditions where good defeats evil, Ohrmazd would defeat Ahriman in combat, the Underworld would empty, and Ohrmazd would real in peace for all eternity. But until that time, Ahriman rules over both the Earth and Underworld, causing sufferring, as he will.
The Deavas, the followers of Ahriman, may have originally been the culture heroes and gods of the early Persians before the influx of Indo-European invaders. The Dualism of good and evil found in Zoroastrianism, and adopted by Judeo-Christian traditions, may have been introduced to convert the Persians away from their old traditions to the new.
In the Zoroastrian myth of Mithra, Ahriman tried to persuade his attendant animals, the scorpion, ant, and snake, to drink the blood of the bull slain by Mithra. If he had succeeded in this, he would have prevented life from forming on Earth. In another legend, he attempted to thwart Ahura Mazda by sending a flood to destroy the world.
Ahriman predates Lucifer in the Christian traditions. His name first appears in the Gathas, or Songs of Zoroaster dating from the seventh century BCE. He is frequently referred to as Lord of Lies, and like his Judeo-Christian and Islamic counterparts, is responsible for all evil in the world. He was never a member of a host of spirits and never fell from grace as his counterparts, Lucifer and Iblis, did. The word deava is the root of the word devil.