The Sister Act characters are four nuns, each with a unique personality. Deloris, Mary Robert, Mary Patrick, and Mary Lazarus are the four nuns featured in the movie. Deloris is a lounge singer who goes undercover as a nun to hide from her mobster boyfriend. Mary Robert is a shy and timid nun who is often overlooked. Mary Patrick is a fun-loving and outgoing nun who loves to dance. Mary Lazarus is an elderly nun who is wise and kind.