In religion, occultism, folklore and fiction, a demon is a being with supernatural powers which are far beyond the ability of any human. It is generally considered to be less powerful than a god or a goddess, although the difference between a demon and a deity is not always clear. The word comes from the Greek daimon which means "spirit" or "divine power".
In modern Western culture, demons are usually considered to be entirely evil beings whose ultimate goal is to destroy all people who come into contact with them, making them suffer greatly before they die. However, some writers on magic have claimed that demons can be conjured and controlled. Skilled magicians are said to be able to learn how to make demons appear and disappear at will and to force them to do their bidding, for example, helping them to become rich.
Demons are often said to have the power to possess animals and people, causing the people who they take over to behave in a manner which is completely out of keeping with the person's previous character. According to religious tradition, a demon can only be made to leave a person's body after a rite of exorcism has been performed by a specially trained religious expert.
In art, demons are usually depicted as being extremely ugly, although they may have the ability to take on any shape they choose. In folklore, they are often described as having a highly unpleasant odor.
In Christian tradition, demons are said to have originally been angels who joined Lucifer in his rebellion against God. After Lucifer was defeated, he and the angels who fought with him were cast down to Hell as punishment. In fiction, demons are often shown as assisting the Devil by helping to torment the souls of the damned in Hell.