Make the Moor thank me, love me and reward me.
For making him egregiously an ass
And practising upon his peace and quiet
Even to madness. ‘Tis here, but yet confused:
Knavery’s plain face is never seen till used.

– William Shakespeare

Othello, Act 2, Scene 1. In Iago’s second soliloquy he reveals his scheme to revenge himself on Othello. He will do this by pretending to be Othello’s friend to gain his love, so that he can destroy Othello’s peace of mind and drive him to madness. Foreshadowed here are Othello’s jealousy-driven descent into madness and the tragic events and deaths that follow. The important theme of appearance vs reality is captured here, as Iago removes his mask to show the "plain face" of his knavery, but only to us the audience. Themes of deception and treachery also feature strongly in Iago’s plotting to destroy his master. He dehumanizes Othello by using an animal metaphor to compare him to "an ass."