Iago is the villain in this play. He is jealous of Michael Cassio's position as Othello's lieutenant, which Iago thinks that he deserves the position more. Iago tells Roderigo that he is taking advantage of Othello, that is the one and only reason why he is serving under Othello and is forced to be his flag-bearer instead of his second in command.
Iago , along with Roderigo shows crafty and devilish ways of coming up with a plan of waking up Brabanzio, and telling him he has been robbed. They tell him that the Moor is sleeping with Brabanzio's daughter Desdemona. Brabanzio thinks they are lying and calls them out as villains.
Iago likes to cause trouble and "stir the pot" or create drama, in act 1.2 he talks to Othello asking him if he is legitimately married to Desdemona.
Also when the senator and his men come find him , Iago tries to easily manipulate him and tell him by "advising" him to go turn himself in. Othello responds to that telling Iago that he has a clear conscious, so he has nothing to worry about.
I just don't like Iago's character. I understand why he is jealous of Cassio and has devilish ways about him, but i just don't like him. I haven't read this play all the way through before , but I hope Iago's character does not turn out worse.