In what way does Emilia’s role develop in Othello?

At the start of the play, Emilia appears to be subservient and manipulated by her husband, Iago, but by the end she has gained in self-confidence and has seen him for the villain he is; finally, she denounces him and reveals his evil to the world. Initially, Emilia does what Iago bids her, despite his lack of warmth to her. Although she feels guilty, she steals Desdemona’s handkerchief for Iago to use as evidence of Desdemona’s infidelity. The audience can understand that Emilia simply wants to please Iago in doing this, saying "I nothing but to please his fantasy," which she quickly regrets when he fails to praise her and she feels remorseful about deceiving her friend Desdemona. It is this friendship that seems to move Emilia to find her moral compass, even though she becomes bitter about her marriage.
 By the end of the play, the submissive Emilia criticizes men in a way that would have been seen as powerful and almost heretical to the Jacobean audience of Shakespeare’s time.  She says "But I do think it is their husbands’ faults/If wives do fall," thus blaming men for leading women astray, which would be unusually opinionated for a woman in the male-dominated patriarchal society of the time. It is ironic that Iago underestimates Emilia, as she finally exposes him for being the cause of so many deaths. Iago has made a mistake based on his own lack of morality and assumptions of others; he never thought that Emilia would betray him and sacrifice herself to "love and duty," which is precisely what she does.