Ah·ri·man 
(ärĭ-mən)
(ärĭ-mən)n.
Ahura Mazda's adversary, the chief spirit of darkness and evil in Zoroastrianism.
[Persian ahriman, from Middle Persian ahraman, from Avestan angrō mainiiuš, the evil spirit : angra-, evil + mainiiuš, spirit; see men-1 in the Appendix of Indo-European roots.]