Hero Complex (Characters question 3)

"Iago: ... And it is thought abroad that 'twixt my sheets/ He's done my office. I know not if't be true,/ . 366But I for mere suspicion in that kind/ Will do as if for surety. He holds me well,/ The better shall my purpose work on him./ Cassio's a proper man. Let me see now,/ To get his place, and to plume up my will/ In double knavery -How, how?- Let's see.-/ After some time, to abuse Othello's ear That he is too familiar with his wife./ He hath a person and smooth dispose/ To be suspected, framed to make women false/ The Moor is of a free and open nature/ That thinks men honest that but seem to be so,/ And will as tenderly be led by the nose/ As asses are." - II. i. v. 367-382

The concepts of protagonist and antagonist are usually very simple. The protagonist is the hero. This character drives the action, and is perspective used to narrate in a novel (or soliloquy in a play). Since this the character usually closest to the audience, they identify with him/her the most and see them as the hero of the story. The antagonist the is the one responsible for stopping the forward motion of the hero, causing problems and complications that the hero will solve with their outstanding wit and incredible daring. Because of these fair and normal stereotypes, the protagonist is the hero and the antagonist the villain. This is not true of "Othello", a factor that makes it's already complex characters. 

Iago is the clear protagonist up to this point. He is in every scene so far and his actions are the ones that move the plot along. He give many soliloquies, the first of which is quoted above. The soliloquy here is the first hint the readers get to where the general idea of Iago's plan is unfolded. It is obvious that his numerous plans drive the novel and its actions. However, it is also revealed that he is not the hero; he is clearly the villain.

Othello's personal thoughts are far less displayed than Iago's. Othello doesn't seem to be an antagonist because he does not try to actively block any of Iago's plans. However, it is his demise that Iago seeks, therefore his mere existence is an opposition to Iago. 

The other characters in the novel are mostly typical foil characters, like Emilia and her typical quietness, but they all serve a purpose in Iago's plan. The character shuffle Shakespeare orchestrates with the personalities of his antagonist and protagonist make "Othello" and confusing, but uniquely interesting play.