In the end, what benefits does Iago receive from his manipulation and deceit in Shakespeare's Othello?
The main benefit that Iago receives is vengeance. At the beginning of the play, he reveals that he is angry at being passed over for a promotion by Othello, who favors Michael Cassio. Later, he even suspects that Othello may be sleeping with his wife, Emilia. His plot is aimed at destroying Othello, and in this, there is no doubt that he is successful. Othello, portrayed as proud and arrogant early in the play, is completely humbled and destroyed by the end, as the Moor himself acknowledges, referring to himself as "he that was Othello." Of course, Iago's plot also destroys the innocent Desdemona, his own wife Emilia, and leaves Michael Cassio wounded. Ultimately, he is left only with whatever satisfaction vengeance brings, because despite his warnings that he will not speak anymore of his plot, he is destined for "torments" before what seems likely to be his death. In any case, the vengeance exacted by Iago is far out of proportion to whatever perceived wrong he suffered at the hands of Othello.