Iago is a pivotal character in Shakespeare's Othello, orchestrating the tragic downfall of Othello and others through manipulation, deceit, and the exploitation of trust. His ability to appear honest while sowing discord allows him to deceive key characters, leading to a chain of tragic events fueled by jealousy, hate, and revenge. Ultimately, Iago's actions reveal the theme that individuals can be profoundly gullible, regardless of their social status or intelligence, as they fall victim to his cunning schemes.