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.
The Devils (film)
Laubardemont summons the lunatic inquisitor Father Pierre Barre, a "professional witch-hunter," whose interrogations actually involve depraved acts of "exorcism", including the forced administration of enemas to his victims. Sister Jeanne claims that Grandier has bewitched her, and the other nuns do the same. A public exorcism erupts in the town, in which the nuns remove their clothes and enter a state of "religious" frenzy. Duke Henri de Condé (actually King Louis in disguise) arrives, claiming to be carrying a holy relic which can exorcise the "devils" possessing the nuns. Father Barre then proceeds to use the relic in "exorcising" the nuns, who then appear as though they have been cured – until Condé/Louis reveals the case allegedly containing the relic to be empty. Despite this, both the possessions and the exorcisms continue unabated, eventually descending into a massive orgy in the church in which the disrobed nuns remove the crucifix from above the high altar and sexually assault it.