A demon is a supernatural, often malevolent being prevalent in various religions, occultisms, literature, and folklore. The original Greek word daimon does not carry the negative connotation initially understood by implementation of the Koine δαιμόνιον (daimonion), and later ascribed to any cognate words sharing the root.
In Ancient Near Eastern religions as well as in the Abrahamic traditions, including ancient and medieval Christian demonology, a demon is considered an "unclean spirit" which may cause demonic possession, calling for an exorcism. In Western occultism and Renaissance magic, which grew out of an amalgamation of Greco-Roman magic, Jewish demonology, and Christian tradition, a demon is a spiritual entity that may be conjured and controlled.
Further information: Daemon, Agathodaemon, Cacodemon, Daimonic, and EudaimoniaBuer, the 10th spirit, who teaches "Moral and Natural Philosophy" (from a 1995 Mathers edition. Illustration by Louis Breton from Dictionnaire Infernal).The Ancient Greek word δαίμων daimōn denotes a "spirit" or "divine power", much like the Latin genius or numen. Daimōn most likely came from the Greek verb daiesthai ("to divide, distribute").  The Greek conception of a daimōns notably appears in the works of Plato, where it describes the divine inspiration of Socrates. To distinguish the classical Greek concept from its later Christian interpretation, the former is usually anglicized as either daemon or daimon rather than demon.
The Greek term does not have any connotations of evil or malevolence. In fact, εὐδαιμονία eudaimonia, (lit. "good-spiritedness") means "happiness". The term first acquired its negative connotations in the Septuagint translation of the Hebrew Bible, which drew on the mythology of ancient Semitic religions. This was then inherited by the Koine text of the New Testament. The Western medieval and neo-medieval conception of a "demon" (see the Medieval grimoire called the Ars Goetia) derives seamlessly from the ambient popular culture of Late (Roman) Antiquity. The Hellenistic "daemon" eventually came to include many Semitic and Near Eastern gods as evaluated by Christianity.
The supposed existence of demons is an important concept in many modern religions[who?] and occultist traditions. Demons are still feared as a popular superstition, largely due to their alleged power to possess living creatures. In the contemporary Western occultist tradition (perhaps epitomized by the work of Aleister Crowley), a demon (such as Choronzon, the "Demon of the Abyss") is a useful metaphor for certain inner psychological processes ("inner demons"), though some may also regard it as an objectively real phenomenon. Some scholars believe that large portions of the demonology (see Asmodai) of Judaism, a key influence on Christianity and Islam, originated from a later form of Zoroastrianism, and were transferred to Judaism during the Persian era.
The classic Japanese demon, an ogre-like creature which often has horns.Psychologist Wilhelm Wundt remarked that "among the activities attributed by myths all over the world to demons, the harmful predominate, so that in popular belief bad demons are clearly older than good ones."  Sigmund Freud developed this idea and claimed that the concept of demons was derived from the important relation of the living to the dead: "The fact that demons are always regarded as the spirits of those who have died recently shows better than anything the influence of mourning on the origin of the belief in demons."
M. Scott Peck, an American psychiatrist, wrote two books on the subject, People of the Lie: The Hope For Healing Human Evil and Glimpses of the Devil: A Psychiatrist's Personal Accounts of Possession, Exorcism, and Redemption. Peck describes in some detail several cases involving his patients. In People of the Lie he provides identifying characteristics of an evil person, whom he classified as having a character disorder. In Glimpses of the Devil Peck goes into significant detail describing how he became interested in exorcism in order to debunk the "myth" of possession by evil spirits – only to be convinced otherwise after encountering two cases which did not fit into any category known to psychology or psychiatry. Peck came to the conclusion that possession was a rare phenomenon related to evil, and that possessed people are not actually evil; rather, they are doing battle with the forces of evil.
Although Peck's earlier work was met with widespread popular acceptance, his work on the topics of evil and possession has generated significant debate and derision. Much was made of his association with (and admiration for) the controversial Malachi Martin, a Roman Catholic priest and a former Jesuit, despite the fact that Peck consistently called Martin a liar and manipulator. Richard Woods, a Roman Catholic priest and theologian, has claimed that Dr. Peck misdiagnosed patients based upon a lack of knowledge regarding dissociative identity disorder (formerly known as multiple personality disorder), and had apparently transgressed the boundaries of professional ethics by attempting to persuade his patients into accepting Christianity. Father Woods admitted that he has never witnessed a genuine case of demonic possession in all his years.
Human-headed winged bull, otherwise known as a ŠeduAccording to the 1906 Jewish Encyclopedia, "In Chaldean mythology the seven evil deities were known as shedu, storm-demons, represented in ox-like form."  They were represented as winged bulls, derived from the colossal bulls used as protective jinns of royal palaces.
From Chaldea, the term shedu traveled to the Israelites. The writers of the Tanach applied the word as a dialogism to Canaanite deities.
There are indications that demons in popular Hebrew mythology were believed to come from the nether world. Various diseases and ailments were ascribed to them, particularly those affecting the brain and those of internal nature. Examples include the catalepsy, headache, epilepsy, and nightmares. There also existed a demon of blindness, "Shabriri" (lit. "dazzling glare") who rested on uncovered water at night and blinded those who drank from it.
Demons supposedly entered the body and caused the disease while overwhelming or "seizing" the victim. To cure such diseases, it was necessary to draw out the evil demons by certain incantations and talismanic performances, which the Essenes excelled at. Josephus, who spoke of demons as "spirits of the wicked which enter into men that are alive and kill them", but which could be driven out by a certain root, witnessed such a performance in the presence of the Emperor Vespasian and ascribed its origin to King Solomon.
Pre-Islamic mythology did not differentiate between gods and demons. Jinns were considered divinities of inferior rank and had many human abilities, such as eating, drinking, and procreating. While most jinn were considered peaceful and well-disposed towards humans, there also existed evil jinns who contrived to injure people.
Lilith, by John Collier, 1892Demons in the Hebrew Bible are of two classes: the se'irim ("hairy beings") and the shedim. The se'irim, to which some Israelites offered sacrifices in the open fields, were satyr-like creatures, described as dancing in the wilderness (Isaiah 13:21, 34:14).
Some benevolent shedim were used in kabbalistic ceremonies (as with the golem of Rabbi Yehuda Loevy), and malevolent shedim (mazikin, from the root meaning "to damage") were often credited with possession. Similarly, a shed might inhabit an otherwise inanimate statue.
Main article: AggadahAccording to some rabbinic sources, demons were believed to be under the dominion of a king or chief, either Asmodai or, in the older Haggadah, Samael ("the angel of death", also called the "chief of the devils"), who killed via poison. Occasionally a demon was called satan: "Stand not in the way of an ox when coming from the pasture, for Satan dances between his horns".
Demonology never became an essential feature of Jewish theology. However, the existence of demons was never questioned by the Talmudists and late rabbis, nor did most of the medieval thinkers question their reality. Only rationalists like Maimonides and Abraham ibn Ezra explicitly denied their existence. Their point of view eventually became mainstream Jewish understanding.
Rabbinical demonology has three classes of demons, though they are scarcely separable one from another. There were the shedim, the mazziḳim ("harmers"), and the ruḥin ("spirits"). There were also lilin ("night spirits"), ṭelane ("shade", or "evening spirits"), ṭiharire ("midday spirits"), and ẓafrire ("morning spirits"), as well as the "demons that bring famine" and "such as cause storm and earthquake".
Main article: Christian demonologyDeath and the Miser (detail), a Hieronymus Bosch painting, National Gallery of Art, Washington DCIn the Gospels, particularly the Gospel of Mark, Jesus cast out many demons or evil spirits from those afflicted with various ailments. He also lent this power to some of his disciples (Luke 10:17). The demons were cast out by the utterance of a name, according to Matthew 7:22, with some groups insisting the original pronunciation of the name "Jesus" be used. The demons or unclean spirits themselves were said to often recognize Jesus as the Messiah. In Matthew 12:43, Jesus taught that when demons were driven from a human, they went through dry places as disembodied spirits seeking respite, although on some occasion he would send them into a herd of swine. Through all accounts, Jesus had never failed in his exorcism of a demon.
By way of contrast, in Acts, a group of Judaistic exorcists known as the sons of Sceva attempted to cast out a powerful spirit without belief in Jesus, but fail with disastrous consequences.
Revelation 12:7-17 describes a battle between God's army and Satan's followers and the latter's subsequent expulsion from Heaven to Earth in order to persecute humans.[clarification needed] Luke 10:18 mentions a power granted by Jesus to cast out demons made Satan "fall like lightning from heaven".
- He [Apulieus] also states that the blessed are called in Greek eudaimones, because they are good souls, that is to say, good demons, confirming his opinion that the souls of men are demons.
The contemporary Roman Catholic Church unequivocally teaches that angels and demons are real beings rather than just symbolic devices. The Catholic Church has a cadre of officially sanctioned exorcists which perform many exorcisms each year. The exorcists of the Catholic Church teach that demons attack humans continually but that afflicted persons can be effectively healed and protected either by the formal rite of exorcism, authorized to be performed only by bishops and those they designate, or by prayers of deliverance, which any Christian can offer for themselves or others.
Building upon the few references to daemons in the New Testament, especially the poetry of the Book of Revelation, Christian writers of apocrypha from the 2nd century onwards created a more complicated tapestry of beliefs about "demons" that was largely independent of Christian scripture.
At various times in Christian history, attempts have been made to classify demons according to various proposed demonic hierarchies.
According to Christian demonology, demons will be eternally punished and never will reconcile with God. Other theories postulate a universal reconciliation, in which Satan, the fallen angels, and the souls of the dead that were condemned to Hell reconcile with God. This doctrine is today often associated with the Unification Church. Origen, Jerome, and Gregory of Nyssa also mentioned this possibility.
In contemporary Christianity, demons are generally considered to be angels who fell from grace by rebelling against God. However, Genesis mentions that Nephilim are a result of the sexual relationships between fallen angels and human women (Genesis 6:2). When these hybrids died they left behind disembodied spirits that "roam[ed] the earth in search of rest" (Luke 11:24). Many non-canonical historical texts describe in detail these unions and the consequences thereof. This belief is repeated in other major ancient religions and mythologies. Christians who reject this view do so by ascribing the description of "Sons of God" in Genesis 6 to be the sons of Seth (one of Adam's sons).
The Majlis al Jinn cave in Oman, literally "Meeting place of the Jinn".See also: Islamic teaching about the Devil and Islamic creationismIslam recognizes the existence of jinn, which are sentient beings with free will that can co-exist with humans (though not the genies of modern lore). In Islam, evil jinns are referred to as the shayātīn, or devils, with Iblis (Satan) as their chief. Iblis was one of the first jinn; he disobeyed God and did not bow down before Adam refusing to acknowledge a creature made of "clay". Thus, Iblis was condemned to hell. He asked for respite until the last day (Judgement Day), when he vowed to make mankind fall and deny the existence of their creator, to which God replied that Iblis would only be able to mislead those who were not righteous believers, warning that Iblis and all who followed him in evil would be punished in Hell.
Asura in Kōfuku-ji, Nara, 734, JapaneseThe Army of Super Creatures - from The Sougandhika Parinaya Manuscript (1821 CE)Originally, Asura, in the earliest hymns of the Rig Veda, meant any supernatural spirit, either good or bad. Since the /s/ of the Indic linguistic branch is cognate with the /h/ of the Early Iranian languages, the word Asura, representing a category of celestial beings, became the word Ahura (Mazda), the Supreme God of the monotheistic Zoroastrians. Ancient Hinduism tells that Devas (also called suras) and Asuras are half-brothers, sons of the same father Kasyapa; although some of the Devas, such as Varuna, are also called Asuras. Later, during Puranic age, Asura and Rakshasa came to exclusively mean any of a race of anthropomorphic, powerful, possibly evil beings. Daitya (lit. sons of the mother "Diti"), Rakshasa (lit. from "harm to be guarded against"), and Asura are incorrectly translated into English as "demon".
In Hindu mythology, pious, highly enlightened Asuras, such as Prahlada and Vibheeshana, are not uncommon. The Asura are not fundamentally against the Gods, nor do they tempt humans to fall. This is markedly different from the traditional Western notions of demons as a rival army of God but comparable with the concept of the jinns in Islam.[contradiction] Many people metaphorically interpret the Asura as manifestations of the ignoble passions in the human mind and as a symbolic devices. There were also cases of power-hungry Asuras challenging various aspects of the Gods, but only to be defeated eventually and seek forgiveness—see Surapadman and Narakasura.
Hinduism advocates the reincarnation and transmigration of souls according to one's karma. Souls (Atman) of the dead are adjudged by the Yama and are accorded various purging punishments before being reborn. Humans that have committed extraordinary wrongs are condemned to roam as lonely, often evil, spirits for a length of time before being reborn. Many kinds of such spirits (Vetalas, Pishachas, Bhūta) are recognized in the later Hindu texts. These beings, in a limited sense, can be called demons.
In the Bahá'í Faith, demons are not regarded as independent evil spirits as they are in some faiths. Rather, evil spirits described in various faiths' traditions, such as Satan, fallen angels, demons, and jinns, are metaphors for the base character traits a human being may acquire and manifest when he turns away from God and follows his lower nature. Belief in the existence of ghosts and earthbound spirits is rejected and considered to be the product of superstition.[25