Aeshma — "Wrath," or more fully Aeshma-daeva, "the Demon of Wrath" — was the chief of the daevas, the demons of the Zoroastrian system. He was the personification of riotous violence, of fury, of the kind of anger that destroys both its object and the one who feels it. He carried a great mace stained with the blood of his victims, and he rode through the world looking for cattle to slaughter, men to incite to murder, and women to drive into wild lamentation. Of all the demons, he was the closest to direct attack on the worshipper, the demon most likely to be encountered in the ordinary disorders of human life.
His Avestan opposite was Sraosha (treated above) — "Obedience," the disciplined attentive listening to the divine word. The opposition is exact: where Sraosha represented the soul ordered by the religious life, Aeshma represented the soul disordered by passion. The two were always paired in the cosmic war, and the worshipper who cultivated obedience to Ahura Mazda was thereby resisting the inroads of Aeshma. The daily Zoroastrian discipline of right thought, right speech, and right action was, on its negative side, an exercise in resisting Aeshma's suggestions.
Aeshma had a remarkable career in late Jewish demonology. The Book of Tobit (composed in the Achaemenid or early Hellenistic period, when the Iranian religion was strongly influencing Jewish demonological speculation) names a demon "Asmodeus" who has fallen in love with the heroine Sarah and who has killed her seven husbands on their wedding nights before they could consummate the marriage. The name Asmodeus is straightforwardly from Aeshma-daeva (Aeshma > Ashmedai > Asmodeus), and the figure is a Jewish-domesticated version of the Iranian demon of wrath transposed into a story of jealous love. The Talmud and the medieval Jewish demonological literature elaborated Asmodeus extensively, making him at once the king of the demons and a figure of considerable folk-narrative interest (the medieval legend of Solomon and Asmodeus is one of the great instances). Christian demonology inherited Asmodeus through the Jewish tradition and continued the elaboration through the Middle Ages, with Asmodeus eventually identified as one of the seven princes of hell.
So the Iranian Aeshma — a relatively minor figure in the Zoroastrian system — became, through the late Jewish reception, one of the most famous demons of the Western religious imagination. His Iranian original is far less developed than his Jewish-Christian descendants, and the comparison gives some sense of how thoroughly the late Jewish demonology drew on the Iranian source while transforming it into something quite different.
