In Shakespeare's Othello, Iago is committed to destroying Desdemona. He realizes this is the most effective way to get back at Othello. Iago hates Othello. Othello overlooked him and named Cassio as his lieutenant. Iago is determined to get revenge.
He is disgruntled at having been passed over for promotion, and he sees a chance to get back at both Othello, who has slighted him, and Cassio, the mocking symbol of that slight.
Iago creates an evil plan to accuse Desdemona of having an affair with Cassio. In this way, Iago can drive a stake in Othello's heart. Othello is madly in love with Desdemona. Iago knows this fact. He uses Othello's jealous emotions toward Desdemona to get back at Othello.
Iago will stop at nothing to see Othello suffer. He knows that the best way to get back at Othello is through the love of his life, Desdemona. Also, Iago hates Othello for his suspicion that Othello has slept with Iago's wife Emilia. For this reason, Iago is determined to use Desdemona to destroy Othello:
I do suspect the lusty Moor [Othello]
Hath leap'd into my seat; the thought whereof
Doth (like a poisonous mineral) gnaw my inwards;
And nothing can or shall content my soul
Till I am evened with him, wife for wife.
Iago is determined to destroy Othello so he sets Desdemona up. Also, Iago manipulates other people in the play to get what he wants. Iago's ultimate goal is to get revenge for Othello's choice of lieutenant and to pay Othello back for sleeping with his wife.
Iaga has a plan to have Roderigo kill Cassio. Iago is evil. He wants Cassio's position. He uses Desdemona as a part of his evil plan.
Iago recognizes that Desdemona is kind. He encourages Cassio to speak with Desdemona after Cassio loses his position as lieutenant. As a master manipulator, Iago twists the facts to further his evil plot. He whispers suggestions to Othello to make it appear that Desdemona and Cassio are having an affair. Because Othello idolizes his wife, he becomes jealous to a point of rage.
Iago knows that Roderigo also loves Desdemona. He uses this fact to turn Roderigo against Cassio. Iago wants Cassio dead. He sets up Roderigo in a plan to get Roderigo to kill Cassio. Desdemona is at the center of Iago's plan. He uses the love Othello and Roderigo have for her to advance his plot.
Desdemona dies as a result of Iago's evil scheme. Iago is one of Shakespeare's most evil villains. He destroyed Desdemona along with Othello. Desdemona means nothing to Iago. Ultimately, Iago is bent on destroying Desdemona because Desdemona is the closest person to Othello.