The Shakespearean play Othello, like other tragedies, is essentially concerned with the decay and downfall of the tragic hero. Othello is this central protagonist whose ruin is ensured from the beginning, however it is in the antagonist Iago that we find the most interesting character. Although Iago may appear to be an honest fellow to the other characters, Shakespeare shows us his true nature. What we see is a manipulative, diabolical, licentious individual who shamelessly attends to his own desires by sowing the downfall of others. This is solidified in the responders mind through Shakespeares careful cultivation of imagery, structure and language.
Throughout Othello we see how Iago manipulates, manoeuvres, and molds the other characters to attend his desires through Shakespeares use of web or net imagery. Iago refers to his plan to ensnare as great a fly as Cassio with the web of his own courtship. This simile of Cassio as a fly suggests that Iago is the scheming spider, pulling strings here and there to catch his prey. We also see Iagos arrogance in that he sees himself as an Ubermensch or superior being, and others as mere prey in his devious plot. Iagos use of this little web also strengthens his character as a master tactician. The web acts as a reference to Iagos devious methods of lies, half-truths, and insinuations in his vast plan to cause the ultimate downfall of those around him. Shakespeare also uses this net imagery to establish Iagos evil and deceptive nature, as seen in his exploitation of the virtue and goodness of others to make the net / That shall enmesh them all (II, iii, 338-339).
Shakespeare further emphasises the devious and deceptive nature of Iago through the use of poison as imagery. Iago uses poisonous words to manipulate the minds of others, specifically Othello, pouring pestilence into his ear (II, ii, 333) and insinuating that Desdemona is committing adultery; just like she deceived her father, marrying you (III, iii, 230). Iagos use of medicine (IV, i, 53), and his reflection that the Moor already changes with my poison (III, iii, 362) further emphasise the plague-like nature of his words. This reflects how Iago is causing Othello to perish; just like poison and disease slowly force their way through the body. Poison is also a typical instrument employed by assassins; thus, Iagos venomous words draw a parallel with the shrewd yet conniving act of secreted, slow murder by poison.
Perhaps most significantly, Shakespeares use of heavenly and diabolical imagery shows how vicious, vile, and villainous Iago truly is. Desdemona is associated with heaven and purity, as suggested by her exclamations of By Heaven and O Heavenly God. Even before her murder, Othello contemplates her complete and utter beauty in his simile Nor that whiter skin of hers than snow. Which uses the colour of white to relate Desdemona to Heaven. Her untainted innocence contrasts poignantly...