Emilia is Iago's wife and Desdemona's lady-in-waiting. It is she who picks up the handkerchief that becomes the proof against Desdemona, and who, in the end, unmasks her husband, paying with her life.
In Act III, Scene 3, Emilia finds the handkerchief that Desdemona dropped and says, alone, that her husband had asked her "a hundred times" to steal it. She hands the handkerchief to Iago and says that only the heavens know what he will do with it. In Scene 4, when Desdemona asks where she lost the handkerchief, she answers: "I know not, madam."
Emilia perceives Othello's jealousy and says that "jealousy comes from jealousy". She defends Desdemona's honesty before Othello, who treats her as a procuress, and, before Iago, says that some villain has worked on the Moor; Iago tells her to speak low and calls her a fool. In Act IV, Scene 3, she tells Desdemona that the fault of women who betray is "all the husbands' fault", because they spend the gold on others, are jealous, restrict and beat.
In Act V, Scene 2, on learning from Othello that her husband had accused Desdemona, she calls the accusation a lie. Iago tells her to go home, she says that obeying him is proper but not now, and reveals the handkerchief. Iago stabs her and flees. Emilia dies singing the refrain of the willow song and telling Othello that Desdemona was chaste.