Iago is brilliant at judging others and their characteristics and uses this to his advantage. He says about Desdemona, “…I will turn her virtue into pitch…”
Iago uses Desdemona’s passion for helping others against her. He convinces Cassio to beg Desdemona to make Othello consider reinstating him as lieutenant. Iago then makes Othello suspicious of Desdemona who so badly wants Cassio to regain his position. This is in fact all part of his master plan to make Othello jealous.
He uses Roderigo’s love for Desdemona and knows that he would do anything to have Desdemona love him in return. Iago tells Roderigo that he will assist him in winning Desdemona’s heart in exchange for money. Iago says regarding Roderigo, “ Thus do I ever make my fool my purse.” By riding on Roderigo’s hopes, Iago is able to fraud Roderigo and make a generous profit for himself.
Iago slowly poisons people’s minds, creating ideas in their heads without compromising his image. Iago, the master of deception says, “And what’s he then that says I play the villain, when this advice is free I give, and honest…”
People rarely stop to wonder whether Iago might be lying to them, which proves just how skilful he is at deceiving others without being detected.
Cassio also follows Iago blindly, thinking that Iago is a friend who is trying to help him. Meanwhile Iago is planning his revenge against Cassio.
On the night Cassio is on guard duty, Iago convinces him to consume alcohol knowing very well that he is easily affected by drinking. Iago is able to make Cassio disregard his own reasoning and manipulate him into having too much to drink.
Once Roderigo follows through with one of Iago’s plans, Cassio is made to look like an irresponsible drunkard. This results in him losing his position as lieutenant. Cassio continues to follow “honest” Iago blindly. He mentions to Iago, “You advise me well.” Cassio is completely unaware that his “trustworthy friend”, Iago, is the cause of his demise.
Even a respected and intelligent man, Othello, considers Iago to be a trusted advisor. He trusts Iago’s words to be truthful because he thinks Iago is a loving friend of exceeding honesty. Iago uses the trust Othello and all the other characters instil in him inn order to turn Othello into a jealous monster, giving cold-blooded Iago the exact result he wanted.