In religions worldwide, any of various evil spirits that mediate between the supernatural and human realms. The term comes from the Greek word daimon, a divine or semidivine power that determined a person's fate. Zoroastrianism had a hierarchy of demons, which were in constant battle with Ahura Mazda. In Judaism it was believed that demons inhabited desert wastes, ruins, and graves and inflicted physical and spiritual disorders on humankind. Christianity placed Satan or Beelzebub at the head of the ranks of demons, and Islam designated Iblis or Satan as the leader of a host of evil jinn. Hinduism has many demons, called asuras, who oppose the devas (gods). In Buddhism demons are seen as tempters who prevent the achievement of nirvana.