An Enemy of the People
Dr. Thomas Stockmann is the undisputed protagonist of the play. Without the Doctor there'd be no play at all. It is his discovery that disrupts the world of the play. It is his quest to reveal the truth of the polluted Baths that drives the action of the play. Everyone is reacting to what he does. Dr. Stockmann is a textbook example of an active protagonist, around whom everything in the play revolves.