Alastor: A vengeance demon named in Collin de Plancy’s Dictionnaire Infernal. In this text, de Plancy indicates that Alastor was known in the Zoroastrian tradition as the Executioner. Although the Zoroastrian connection is dubitable, in the tradition of the ancient Greeks, Alastor was indeed a spirit of vengeance. Zeus was known as Zeus Alastor whenever he assumed a vengeful form. In Waite’s presentation of the Grand Grimoire from his 1910 Book of Black Magic and Pacts, Alastor is described as Hell’s Commissioner of Public Works. He is also portrayed as an infernal judge. These attributions tie back to the work of Charles Berbiguier, a self-styled demonologist from the early nineteenth century.

SOURCE :

The Dictionary of Demons written by Michelle Belanger