Michael Cassio is young, handsome inexperienced soldier and Othello's lieuenant, whose high position is much resented by Iago. Cassio is a smooth-talking, very courteous Venetian courtier, the opposite of Othello in many respects, which is why Othello admires him, oddly enough , Cassio is extremely ashamed after being implicated in a drunken brawl on Cyprus and losing his place as lieutenant. Iago uses Cassio's youth, good looks, and friendship with Desdemona to play on Othello's insecurities about Desdemona's fidelity.