Exorcism
In Christianity, exorcism is the practice of casting out demons. In Christian practice the person performing the exorcism, known as an exorcist, is often a member of the Christian Church, or an individual thought to be graced with special powers or skills. The exorcist may use prayers and religious material, such as set formulas, gestures, symbols, icons, amulets, etc. The exorcist often invokes God, Jesus and/or several different angels and archangels to intervene with the exorcism. Protestant Christian exorcists most commonly believe the authority given to them by the Father, Son, and Holy Spirit (the Trinity) is the source of their ability to cast out demons.
Exorcism
In Taoism, exorcisms are performed because an individual has been possessed by an evil spirit for one of two reasons. The individual has disturbed a ghost, regardless of intent, and the ghost now seeks revenge. An alive person could also be jealous and uses black magic as revenge thereby conjuring a ghost to possess someone. Members of the fashi, both Chinese ritual officers and priests ordained by a celestial master, perform Chinese rituals, in particular, exorcisms.