Othello represents how jealousy, particularly sexual jealousy, is one of the most corrupting and destructive of emotions. It is jealousy that prompts Iago to plot Othello’s downfall; jealousy, too, is the tool that Iago uses to arouse Othello’s passions. Roderigo and Bianca demonstrate jealousy at various times in the play, and Emilia demonstrates that she too knows the emotion well. Only Desdemona and Cassio, the true innocents of the story, seem beyond its clutches. Shakespeare used the theme in other plays, but nowhere else is it portrayed as quite the “green- eyed” monster it is in this play. Since it is an emotion that everyone shares, we watch its destructive influence on the characters with sympathy and horror. Jealousy is the main factor that appears to destroy Othello.
Iago is the initiator of the chain of events that sparks jealousy in Othello, and eventually leads to the downfall of not only the main character, but also of most of the significant characters in the book.