Isabella is Claudio’s sister, a devout, unbending novice to the order of Saint Clare, though she does not find them rigorous enough and wishes she could be even more strongly restricted by them.
She is convinced by Lucio to plead for her brother’s life to Angelo, though needs the fop’s instructions on how to do so; she finds it a difficult task given that she quite agrees with Claudio’s death sentence and the reasoning behind it. She is fixated on her chastity and convinced that everyone holds it as highly as she does herself; she rejects all arguments distinguishing between chastity and virginity. Betrayed first by discovering that Angelo, an admirable man from her point of view, has become a lustful hypocrite, then by finding out that Claudio would prefer she let herself be raped rather than he be executed, she is consoled by the disguised Duke. She accepts his plan despite its questionable morality. She likes Mariana, and is persuaded by her to plead for Angelo’s life. She does not easily manage emotions other than judgmental anger, and is possibly a repressed masochist. Her reaction to the Duke’s proposal of marriage is unknown, though it is noticeable that he has to ask her twice.