Who is the main antagonist in Shakespeare's play 'Othello'?

Iago is a fictional character in Shakespeare's 'Othello'. Iago is the play's main antagonist, and Othello's standard-bearer. He is the husband of Emilia, who is in turn the attendant of Othello's wife Desdemona. Iago hates Othello and devises a plan to destroy him by making him believe that Desdemona is having an affair with his lieutenant, Michael Cassio.

Iago is one of Shakespeare's most sinister villains, often considered such because of the unique trust that Othello places in him, which he betrays while maintaining his reputation for honesty and dedication. Shakespeare contrasts Iago with Othello's nobility and integrity. With 1,097 lines, Iago has more lines in the play than Othello himself.

Iago is a Machiavellian schemer and manipulator, as he is often referred to as "honest Iago", displaying his skill at deceiving other characters so that not only do they not suspect him, but they count on him as the person most likely to be truthful.

Iago is a soldier who has fought beside Othello for several years, and has become his trusted advisor. Iago plots to manipulate Othello into demoting Cassio, and thereafter to bring about the downfall of Othello himself. He has an ally, Roderigo, who assists him in his plans in the mistaken belief that after Othello is gone, Iago will help Roderigo earn the affection of Othello's wife, Desdemona.