Cassio
Cassio functions as Iago's first target and the unwitting engine of the handkerchief plot — his disgrace, his charm, and his innocent friendship with Desdemona are each in turn reshaped into evidence against her. His survival to the play's end, restored to the rank he lost, provides one of tragedy's few notes of continuity amid the wreckage.
Appears In
Biography
Cassio is Othello's newly appointed lieutenant, a Florentine soldier whose promotion over the more experienced Iago is the wound that sets the entire tragedy in motion. He is courteous, well-spoken, and easy in the company of women in a way Iago immediately identifies as a vulnerability — describing him, with characteristic contempt, as having 'a daily beauty in his life' that makes Othello's own bearing look coarse by comparison.
Iago's first move against him exploits a genuine weakness: Cassio's poor tolerance for drink. Manipulated into a night of carousing while on watch, he is provoked into a brawl with Montano and stripped of his lieutenancy by Othello on the spot, delivering the self-lacerating verdict that he has lost 'the immortal part' of himself — his reputation. His desperation to recover that reputation, and his decision to seek Desdemona's help in doing so, is precisely the opening Iago needs to suggest an affair between them.
Cassio survives the play's carnage more by accident than design — Roderigo's attempt on his life in the dark streets of Act V wounds rather than kills him, and it is Iago, moving to silence a witness, who inflicts the more serious injury. Restored to Othello's trust only after the truth of Iago's plot is revealed, Cassio inherits command in Cyprus at the play's close, a position gained at a cost he had no part in creating.
Motivation
Cassio is motivated above all by his sense of honour and reputation, particularly after his public disgrace; his desperate campaign to be reinstated in Othello's good graces is what drives him to seek Desdemona's intercession, unaware of how thoroughly that request will be turned against them both.
Personality
Cassio's easy charm and good manners, genuine assets in peacetime Venice, make him legible to Iago as an exploitable type — a man whose reputation matters to him more than almost anything else, and whose sociable warmth toward women can be recast as impropriety by anyone willing to lie about it. His shame after the drinking scene is sincere and immediate, revealing a man whose honour, unlike Iago's performed version of it, is not merely strategic.