Othello and Iago are the two main characters in 'Othello' and they represent the stereotypical cliché of 'good versus bad.' Othello, the noble, honest and brave general represents good, whereas Iago, the bitter, evil, misogynistic lieutenant represents everything evil and destructive. Despite their differences, they have been friends for many years, as Iago has not revealed his malevolent characteristics. He pretends to be a perfect gentlemen and a friend of the community when he is persistently perceived as “honest Iago,” yet as the tragedy unfolds, Iago's true colours are revealed. However, Iago's character does not change throughout the play - he was evil in the beginning and remains evil when the play concludes. In contrast, the mannerisms and actions of Othello change dramatically for the worse as the play progresses and the root cause of this is Iago. Iago is very much the instigator of everything evil in the play; he is the catalyst for evil. The relationship between the two main characters is ever-changing as Iago's plot becomes more sinister and his grip over Othello tightens.
Iago's hatred for Othello clearly stems from bitterness for not being promoted as “the moor's” lieutenant. Immediately, Iago shows signs towards jealousy of Cassio, “a Florentine,” who got promoted as Othello's right-hand man, “Forsooth, a great arithmetician.” Iago is shocked and appalled that he has been overlooked by his long-term friend Othello, who has instead turned to a foreigner that lacks battlefield experience. The decision to appoint Cassio in the position coveted by Iago is the obvious reason for his hatred of the Moor. He plots Othello's downfall, presumably for revenge, though his motives are unclear. Once he's supplanted Cassio and been named as Othello's lieutenant, long before anybody has died, Iago doesn't stop. This shows it was more than just the job he wanted, and his talk of the “lusty Moor … leaping into his seat'' is entirely implausible. This shows either Iago was truly hurt by the appointment of Cassio so much so he wanted to bring death to him and others, or that there was other, more deep motives. There is more reason to suggest the latter as Iago appears jealous of Othello, he is a racist, or as Samuel Taylor describes, Iago shows “motiveless malignancy,” meaning that he has no motives for his evil deeds (Adamson, 98).
The relationship between Othello and Iago is of a friendly nature to begin with although before we see the two characters together, Iago has already slurred Othello's good name. The first time they speak in Act 1 scene 2, Iago is already deceiving Othello. He pretends to be angry with Roderigo for insulting 'the moor', “Nay, but he prated …provoking terms,” and he acts like a friend and supports him, which only enhances Othello's trust. There is no denying that Iago is clever - he knows of his high status and how he is perceived in Venice. This advantage is vital in the deception and manipulation of Othello, as he knows of Othello's naïve ...