Father Karras is a fictional character from the novel and film The Exorcist, created by William Peter Blatty. He is a Jesuit priest and psychiatrist who struggles with his faith and personal demons while investigating a case of demonic possession. Karras is portrayed as compassionate and conflicted, often questioning his beliefs and the existence of evil. In the story, Father Karras becomes involved in the exorcism of a young girl named Regan MacNeil, who is possessed by a demon. His character represents the battle between science and religion, as he seeks to understand the supernatural while grappling with his own crisis of faith.