In religion and mythology, a demon is a supernatural being, usually malevolent being. In Hindu mythology, gods are known as ‘suras’ and the demons or "non-gods" are called “asuras.” In the earliest Rig Veda hymns, the term asuras (Sanskrit: असुर), were used for any supernatural spirit, irrespective of the fact whether the spirit exerted good or evil influence, for example, the deities, Varuna and Mitra, were referred to as asuras. In the later part of Rig Veda the term came to be applied to the enemies of the gods. In the Atharva Veda, and in the Epic literature, the asuras are demons, giants and goblins, symbolizing evil, darkness, drought and hampering sacrifices and rituals. Asuras as supernatural beings are also referred to in traditional Buddhist cosmology.
Watch a Sand Art depiction of one of the mythological tales featuring demons and the Hindu "Monkey God", Lord Hanuman.
According to the Hindu theory of reincarnation and transmigration of souls, human beings that with extraordinary bad karma are condemned to roam as lonely, often evil, spirits before being reborn. These roaming evil spirits, known as vetalas, pishachas, bhoot) can be called demons, by virtue of their evil temperament.
The Holy Bible identifies demons as fallen angels under the command of Satan, causing death, illness, lost power, demonic possession and influence. The power of Satan is summarized in Psalm 109:6-13 – “He can blind true religion, shorten life (where God permits), remove people from authority, can kill, can persecute children, remove wealth, turn everyone against you, he can cut off posterity to the second generation.”