D'Kay was a powerful demon that lived in a realm known only as the pit. He attempted to destroy the humans of Earth by exploiting unsuspecting human-beings through their sins and granting them super-powers to carry out his wishes. He duped these humans into believing that they were super-heroes and that the only righteous and moral beings were them. They took on the name of the Legion of Vengeance, and their names were Bacillus, Mind's Eye, Strontium-90 and Vesper. D'Kay's demonic schemes were foiled by Ghost Rider
(Danny Ketch) and Iron Fist
(Danny Rand), although, D'Kay promised that he would return.