As a fan of Shakespeare’s plays I knew to expect a tragedy even before opening the book but this one seemed hopeless from the start. It was clear that Iago was too ambitious. There was no way out for Othello without actually questioning Cassio himself but he was unwilling to do that. He didn’t want to have to ask and have it confirmed but he allowed jealousy to take over anyway. Othello seems to be very stubborn in his way of thinking. When he believed in Desdemona he believed in her wholeheartedly and would defend her to anyone but once he see’s and hears what he believes is proof of her infidelity he becomes hell-bent on the idea that she is unfaithful. Nothing she or anyone else says will change his mind. That is until he has murdered her.
In acts one through four Iago is very sure of his strategy to become lieutenant. He see’s no way of his plan backfiring on him. But at the start of act 5 Iago comes to the realization that if Cassio survives his plans will be destroyed, and Othello could find out the truth. Which essentially set the stage for the finale.