Desdemona is the daughter of Senator Brabantio who marries Othello, accompanies him to Cyprus and ends up killed by him, who accuses her of a betrayal that she denies to the end.
In Act I, Scene 3, her father calls her before the Senate to say to whom she owes obedience. She answers: "I perceive here a divided duty." She recalls that her mother, on marrying, put her husband before her father. She says that she did love the Moor "to live with him" and asks to follow him to Cyprus.
In Act III, Scene 3, she promises Cassio to intercede for him and speaks of it to Othello more than once. In Scene 4, when Othello asks for the handkerchief, she says he "was not lost", though she has just asked Emilia where he lost it, and returns to speaking of Cassio, while Othello only repeats "The handkerchief!"
In Act IV, Scene 1, she is slapped before Lodovico; in Scene 2, Othello asks who she is and treats her as a whore, and she answers: "Your wife, my lord, your chaste and loyal wife." She asks Emilia to spread the marriage sheets on her bed and sings the willow song. In Act V, Othello smothers her. She denies it to the end and, asked by Emilia who killed her, says: "Nobody. I myself. Farewell."