An Exorcist is a person who expels demons. Most exorcists are priests, clergy, or adepts; some laypersons call themselves exorcists. Exorcists use specific prayers and rituals to cause demons to leave people and/or places, either of their own volition or by force.
Beliefs about the ability of spirits to interfere in human life and cause problems, including disease and misfortune, are widespread. Jesus was noted for his ability to exorcise demons. Specially trained persons who cast out demons are found universally since ancient times. According to some beliefs, persons are born with the special ability to battle demons. Reginald Scot wrote in the 16th century that a person born with Mars in the ninth house has the power to expel demons from the possessed. In the Catholic Church, any priest can be an exorcist. While it is desirable that an exorcist lead the most virtuous life possible, even priests who live in mortal sin can function as exorcists, albeit probably not as effectively as their more virtuous counterparts. Since attitudes toward demonic interferences vary, not all dioceses have official exorcists; sometimes, they are concentrated in archdioceses. Priests who perform many exorcisms are likely at some point to be subjected to criticism and ridicule from their peers.