I would have to say that I think that Cassio and Roderigo are just pawns that Iago uses for his own gain. This is quite obvious but what did Shakespeare intend them to be? I believe Iago to be the most important and central character. Shakespeare therefore I believe is very keen to develop his character and give him what he needs to make his revenge plots successful. He presents Iago with Cassio and Roderigo two puppets he can control and manipulate.
Jealousy, hatred, and selfishness what do you get when you put all those together you happen to get Iago. iago happens to get much enjoyment in causing chaos with the whole environment around him and he is very good at doing it especially with the moors (Othellos) trust. The moor Othello happens to think Iago is a loyal servant and a trusting man but every now and then he has his doubts but the doubts aren’t that strong. In reality a general should be very head strong and intelligent and be able to see through a plan like Iago’s. Of course this does suit Shakepeares purpose and it makes things more interesting to create dramatic irony and make Othello a bit naive. With Othello giving him all this trust he in a way invites Iago to come in and check out the environment and in Iago's head that is an invitation to come and fool around with every ones head. Iago in act one starts his jealousy by telling Roderigo Othello not giving him the position of lieutenancy he has given it to Cassio. This really makes Iago mad so the way that he decides to get back at Othello is by telling Brabantio that his daughter has been kidnapped by Othello but the trick is that Iago uses Roderigo sort of as a pawn he works into his head when both of them go to wake brabantio he makes Roderigo do all the dirty work of calling out his name and telling him the truth you can see this when Iago says
