Cassio: The Man Destroyed by Someone Else's War

Cassio is Iago's target before Othello is. He got the lieutenancy Iago wanted, and Iago resents him for it with a specificity ('Mere prattle without practice is all his soldiership') that tells us more about Iago's bitterness than about Cassio's actual abilities.

Cassio is not particularly clever. He drinks when he should not, which is how Iago engineers his disgrace in Act 2, Scene 3. He visits Desdemona to plead for reinstatement without imagining that Iago will use those visits as evidence. He is a decent man who lacks the tactical self-awareness that survival in Iago's presence requires.

He survives the play (wounded but alive) and is left as Governor of Cyprus, the position Othello held. It is not a triumphant ending. He inherits a post soaked in tragedy, and the play offers him no moment of clarity about how close he came to being destroyed entirely.