Cast of The Exorcist III

George C. Scott plays Lt. William 'Bill' Kinderman, a police lieutenant investigating a series of murders.

Ed Flanders portrays Father Joseph Kevin Dyer, a priest who helps Kinderman in his investigation.

Brad Dourif takes on the role of James Venamun / The Gemini Killer, a man connected to the mysterious murders.

Jason Miller plays Father Damien Karras / Patient X, a character with ties to the original events of possession.

Nicol Williamson plays Father Morning, a priest with insights into the supernatural.

Scott Wilson portrays Dr. Temple, a character involved in the hospital's treatment of the patients.

Nancy Fish plays Nurse Allerton, a staff member at the hospital where the events unfold.

George DiCenzo plays Stedman, a supporting character in the investigation.

Don Gordon portrays Ryan, another character involved in the police investigation.

Lee Richardson plays the University President, a figure within the academic setting.

Grand L. Bush portrays Sergeant Atkins, a police sergeant working with Kinderman.

Mary Jackson plays Mrs. Clelia, a character with connections to the mystery.