Sister Aloysius is the principal of the St. Nicholas school. She is stern, suspicious, and cynical, making a point of showing the students no weakness and discouraging signs of weakness in the nuns under her. When she is first introduced, her suspicious nature seems excessive: she suspects a boy who went home with a nosebleed of having intentionally inflicted it himself, and she feels that ballpoint pens, as opposed to fountain pens, offer students the easy way out. Her dour attitude makes her unsympathetic, and audiences are left to wonder whether, as Father Flynn and Sister James speculate at different times, she is suspicious of Father Flynn only because she personally dislikes his compassionate
