Iago is an example of the typical stage Machiavel who personifies... self-interest, hypocrisy, cunning
Iago is a character so conducted, that he is from the first scene to the last hated and despised.
Iago is appealing to us as more amusing than other characters because his victims lack humour.
Iago has a cool malignity. He is silent in his resentment, subtle in his designs, and studious at once of his interest and vengeance.
Iago is motivated by his racial prejudice to try to engineer it so that Othello's deeds fit in with the prejudice that his face excites.
Iago is a kind of working-class hero whose actions are politically justified as a legitimate grudge against a bourgeois system that has oppressed him.
Iago is given a dramatic perspective by Shakespeare which compels us to see with Iago's eyes and to share his jokes. His humour also makes him seem cleverer than his victims.