Iago is the main antagonist in William Shakespeare's tragedy Othello. He is a manipulative and scheming character who plots to bring down the title character, Othello. Iago is driven by his jealousy of Othello's success and his desire for revenge against Othello for passing him over for a promotion. He is a master of deception and uses his skills to manipulate the other characters in the play. He is ultimately responsible for the downfall of Othello and his own death.