He lived during the early 20th century, having witnessed the Stock Market Crash of 1929. After he killed his murder victims, he would bury their bodies on a deer hunting ground. Sometime in 1933, while burying the body of one of his victims, he was shot and killed after being mistaken for a deer by a hunter. This is why his demon form shares many characteristics with that of a deer.[note 1]
When Alastor arrived in Hell, he possessed unimaginable raw power, which was never before seen in a human soul. He quickly trampled powerful demons who had been in charge for centuries and then broadcasted this carnage on the radio for everyone to hear. Other denizens would begin referring to Alastor as "The Radio Demon", and he eventually grew powerful enough to rival the Overlords of Hell; it is implied that he managed to defeat or kill an Overlord and subsequently took their place. While many demons recognized his power and standing, several scorned him including the TV demon Vox and the two began to see each other as hated rivals.
Sometime after he established himself he took a more casual approach to things. At this time the only demons that didn't run or show signs of fear around him were a group of ladies from the Cannibal Colony who instead are friendly and even swoon over him. After he visited a butcher shop to procure some venison, Alastor overheard the owner trying to force himself on another patron. He quickly returned and tore apart the butcher, leaving after taking some meat for himself with his prior order.
After several decades of "lacking inspiration" and feeling rather aimless, he happens to come upon Charlie on TV and watches her brawl with Katie Killjoy. Finding the idea of a rehabilitated demon absurd (yet entertaining at the same time), he decides to help Charlie run her hotel but instead to watch sinners try and fail to better themselves. Upon introducing himself, he goes around bringing in some help to run the hotel including Niffty & Husk. Upon hearing a ruckus outside, he notices Sir Pentious arrive who tries to intimidate them; he merely grins maniacally and summons several eldritch tentacles that contort and destroy the ship Pentious was aboard. After the ship explodes into a fireball, Alastor leads the way back to the hotel and remarks that this endeavor was going to be the "start of some real changes down here."