Othello's downfall was caused by a flaw in his nature that was exploited by Iago and manipulated through many circumstantial events. Othello is, by nature, a very trusting person. His job as the general is to make decisive decisions, this means all that is needed is for Iago to push Othello a little in the direction he wants, and Othello will make a decision, such as killing Desdemona, which he will follow through without thinking twice. Othello's downfall is caused by Iago's plot against him; Iago uses Othello's human nature as a key to his psyche, and manipulates him as he pleases.

Othello's first major flaw is his gullibility and trusting in people. Othello is manipulated by Iago numerous times without Iago supplying evidence of his claims. "Iago: I speak not yet of proof. Look to your wife; observe her well with Cassio; /.../Othello: I am bound to...