Alastor refers to several entities in myth. His name means "avenger" and in Greek myth he is an avenger of evil deeds especially family feuds. He inflicts vengeance upon the sons for the sins of their fathers. Alastor is mentioned in Christian demonology as a term for a class of evil spirits and was also an entity compared to Nemesis and is demonic in vengeance. In Zoroastrianism he is simply known as the "executioner" or "tormenter".