Alastor was a man who lived in New Orleans, Louisiana, during his life, where he worked as a radio host while leading a double life as a cannibalistic serial killer. He died in 1933 after being shot by a hunter while disposing of a body. After death, he became a Sinner demon and settled in the Pride Ring of Hell. Currently one of the powerful Overlords, he is known as the "Radio Demon" and the "Strongest Sinner," standing at 213.8 cm tall. His appearance is dominated by red, featuring red hair, eyes, and attire. He has deer ears and small antlers on his head, which grow larger when his emotions intensify. His body shows signs of both deer and voodoo doll characteristics, with marks resembling green thread stitching. He possesses a unique voice that sounds as if it is coming through a radio and carries a cane topped with a radio microphone. His most prominent trait is that he maintains a smile under any circumstances. Whether he is angry, in combat, or even in life-threatening danger, he strives to keep smiling. However, he is far from benevolent; he enjoys the misfortune and suffering of others. He is highly intelligent and calculating, always manipulating contracts to his own advantage. As a powerful Overlord, he possesses various abilities including demon transformation, shadow manipulation, voodoo magic, ventriloquism, summoning familiars and giant tentacles, reality warping, and pyrokinesis. He can hide within shadows to evade attacks or travel to different locations. A peculiar phenomenon occurs where filming him with cameras or camcorders causes severe screen glitches or device failure. He enjoys jambalaya, venison, and strong spirits like whiskey, but dislikes sweets and dogs. He also detests modern visual media and electronics such as TVs, smartphones, and tablets, insisting on using the radio. Currently, he serves as an investor and host of the Hazbin Hotel, as well as the hotel's FM broadcaster. His sexual orientation is asexual, though he does not seem fully aware of the term himself. He has a mother whom he holds in high regard.