A demon is a malevolent supernatural entity. Historically, belief in demons, or stories about demons, occurs in folklore, mythology, religion, occultism, and literature; these beliefs are reflected in media includingfiction, comics, film, television, and video games. Belief in demons probably goes back to the Paleolithic age, stemming from humanity's fear of the unknown, the strange and the horrific. In ancient Near Eastern religions and in the Abrahamic religions, including early Judaism and ancient-medieval Christian demonology, a demon is considered a harmful spiritual entity that may cause demonic possession, calling for an exorcism. Large portions of Jewish demonology, a key influence on Christianity and Islam, originated from a later form of Zoroastrianism, and was transferred to Judaism during the Persian era.
Demons may or may not be considered to be devils: minions of the Devil. In many traditions, demons are independent operators, with different demons causing different types of evils (destructive natural phenomena, specific diseases, etc.) in general, while devils appear more often as demons within a theologial framework; demons opposing the Divine principle. As lesser spirits doing the Devil's work, they have additional duties— causing humans to have sinful thoughts and tempting humans to commit sinful actions.