Even if you’re not religious, you’ve got to give religions credit for at least one thing: they really know how to scare the living hell out of people. Religious demons often sound more terrifying than anything a human could dream up, which isn't a bad way to keep potential sinners in line.
This list of demons from religion includes figures from many different faiths. Christianity, Judaism, Buddhism—if it’s got an evil demon, it’s probably here. Some of these are familiar, some of them are obscure, but they’re all really scary.
What happens when you have sex with a mountain? If you answered, “Your union creates a race of rock children, duh,” you’re totally right, but you probably shouldn’t be cheeky, because that’s a really weird thing to know. Asag is a grotesque, hideous demon from Sumeria who leads his rock-children-things in battle. He’s so monstrous to look at, according to legend, he causes fish to boil alive.
An incubus is a male demon that appears to women during erotic dreams. The incubus then attacks the woman by raping her, and subsequent encounters can cause serious illness and death. If you think you’ve got an incubus pestering you, run, don’t walk, to your nearest exorcist.
Have you ever heard the phrase “I am legion,” signifying solidarity with a particular group? You probably wouldn’t have guessed that the phrase comes from the story of a possessed man in the Bible. Jesus comes across an unnamed man who is plagued by a demon. He performs an exorcism, and in order to cast the demon out, he asks it for its name. It responds, “My name is Legion, for we are many.” Which is simultaneously incredibly badass and incredibly terrifying.
Rangda is part of Balinese mythology and closely tied to Hinduism. She is a widow who thirsts for revenge and eats children. She has supernatural powers and commands an army of witches against Barong, who is the complete opposite of Rangda. She is depicted as a grotesque old woman.