Aeshma (Aēšma) is the Younger Avestan name of Zoroastrianism's demon of "wrath", with his wrath being mainly directed towards the cow. As a hypostatic entity, Aeshma is the personification of violence, with himself being the lover of war and conflict. Along with the demon of death, Asto Vidatu, he chases the souls of the dead when they rise towards heaven. His standard epithet is "of the bloody mace", with his eternal enemy being Sraosha. He servers as the messenger of Ahriman, and is also closely associated with Az, the demon of lust.
The name Asmodaios or Ashmedai, derived from Aeshma-daeva, can be also found in the Old Testament Book of Tobit. He also appears in some Talmudic tales, which often portray him as lustful. They also associate him with the reign of king Solomon, who tricked this demon into partaking in the construction of the Temple of Jerusalem. He would later be turned by Christian writers into Asmodeus, a demon lord representing lust - he's described this way in Mallelus Maleficarum and in Peter Binsfield's Treatise on Confessions by Evildoers and Witches.
Aeshma is a DLC demon and a palette swap of Asmodeus. He is fusable after defeating all four archangels in the two Clipped Wings DLC Challenge Quests, where Mastema hands over his data. Alongside Minotaur, Aeshma was one of the demons wielded by Akira.
Aeshmas appear in the Caracol and the Scorpio/Aquarius/Taurus/Leo Temples as common enemies, and later reappear in the Control Room of the Abandoned Factory. A conversation with Armaiti reveals that his female appearance is merely a disguise.