As fast as William Shakespeare could write his plays, there have been people there to criticize and pick apart his work. This is not surprising, when you stop to look at the underlying meanings in Shakespeare's writing. Shakespeare's play Othello is no exception for these critical eyes, with its tale of revenge, love, jealousy, and murder. And, as with any story, the play has its villain that causes the main conflict. Iago, Othello's "trusted" advisor and supposed friend, is that villain in the story of Othello. Iago is the cause of the downfall of the main character, Othello, and it is hard to tell if Iago is motivated by human desires, or simply the embodiment of evil. Iago is not the ideal human being, but looking at his motivations for what he does helps point out that he is simply acting on human feelings. .
First of all, it is Iago's own human desires that lead him to do the things he does. At the beginning of the play, Iago is having a conversation with Roderigo, in which Iago says "I know my own price, I am worth no worse a place. But he, as loving his own pride and purposes, evades them with a bombast circumstance horribly stuffed with epithets of war, and in conclusion non-suits my mediators. For "Certes," says he, "I have already chose my officer."" (I.1, 11-17). When Iago makes this statement, he shows his bitterness towards Othello for promoting another soldier, Cassio, over himself. This makes Iago so mad that he comes up with this plot to bring down Othello as well as Cassio. Jealousy and bitterness are very common human characteristics, not necessarily evil ones. To have these feelings is natural and it does not make you "the embodiment of evil".
Furthermore, Iago's motivation for plotting against Othello is revenge, not just pure evil. He plans to get close to Othello, to the point where Othello places a great deal of trust in him. That puts Iago in a position to get inside Othello's head and bring him down using his own thoughts.