Othello is a tragedy written by William Shakespeare, Poet and Playwright, in the 1600's. Iago is a major character pivotal to the story's outcome and development. He is the main antagonist of the play, but not pure evil; displaying multiple personality traits including villainous, jocular, and deceptive qualities amalgamating into an identity generally perceived to be wicked. His basic aim is to destroy the lives of Othello and to a certain extent, Cassio (any other lives that are also affected are a bonus). While that is his objective, it is not his motive, - not to suggest that he has any. Iago is a "motiveless malignancy", in the sense that, all his actions are caused by personal desires or reactions to circumstances. He doesn't have any motives, as he has nothing qualitative to gain from his actions. Love or emotion, true or not, serves an important part in his plan and Iago, himself is influenced by it. He goes beyond the minimum requirements for certain objectives, i.e. to replace Cassio as Lieutenant, raising doubts as to whether he enjoys deceiving others, or is captured in his own web-trap of lies. Iago is a complicated man who commits crimes not out of motive, but for other objectives stemming from his personality, and surrounding circumstances.Iago does not proactively perpetrate his plan; rather it is in retaliation for injustices that he believed were inflicted on him. He hates Othello for promoting Cassio, an accountant with no war experience whatsoever, to Lieutenancy, over himself. Iago decides to quietly respond, by destroying Othello's life. In the play, Iago only stated that he hated "The Moor", but never why he did so. It makes one wonder, why he hates his boss, even though Othello holds Iago in the highest esteem. "My friend, thy husband, honest, honest, Iago." ~ Othello to Emilia (5.2.153). Everyone till the climax, every major character, especially Othello, believes Iago to be honest. That belief could not have been held so firmly since the start of the play, as a certain back-story and relationship between Iago and him (Othello), would have been required for Othello to truly believe that he (Iago) was honest. "At Rhodes, at Cyprus, and on other grounds Christian and heathen, must be lee'd and calmed." ~ Iago talking to Roderigo about previous battles alongside Othello (1.1.29-30). Othello does acknowledge that, they had worked together previously, and that leads to the likelihood of a previous friendship between the two. Failure to be promoted could lead to feelings of betrayal in Iago's mind, causing anger and instigating desire for revenge.Although the main reason for his vengeance is his irritation of not being promoted, jealousy of the person who did receive the promotion is a related cause. Another root for his envy was his belief that Othello was sleeping with his wife, Emilia."I hate the Moor, And it is thought abroad that 'twixt my sheets. He's done my office. I know not whether if't be true. Yet I, for mere...