Response to part of question 3-role of minor characters

"I will not charm my tongue, I am bound to speak. My mistress here lies murdered in her bed." (V.ii.183-184)

These are the words of Emilia, wife of Iago. In many ways, this minor character completely changes the plot. Without the presence of Emilia at the end, Iago possibly would have gotten away with his heinous plan. After being quiet and walked on by her husband in Act 2, she stands up for herself; rather, she actually stands up for Desdemona. Since the stakes and motivation has changed, she decides she won't let her husband get away with  deceiving Othello, Cassio, Roderigo, and all the other people he lied to. Had it not been for her intervention, Iago most likely walks away a free man ready to ruin someone else's life. One other significance of Emilia is revealed early. Iago claims his motive for revenge against the Moor is that he supposedly slept with Emilia. Later this was dispelled; whether it was true or not, whether it even mattered to Iago, it was one of the motives he revealed.