In Act 1, Scene 1, Lear drives Kent out of his castle as punishment for his insubordination. In Act 1, Scene 4, the audience bears witness to Kent’s attempts to return to the castle—this time, in disguise:
If but as well I other accents borrow,
That can my speech diffuse, my good intent
May carry through itself to that full issue
For which I razed my likeness. Now, banished Kent,
If thou canst serve where thou dost stand
So may it come thy master, whom thou lov'st,
Shall find thee full of labors.
Thanks to this scene, the audience will know that Caius is, in fact, Kent in disguise. When Caius then declares his intent to serve Lear as a faithful servant, his speech is rife with dramatic irony:
I do profess to be no less than I seem—to serve him truly that will put me in trust, to love him that is honest, to converse with him that is wise and says little, to fear judgement, to fight when I cannot choose, and to eat no fish.
Only the audience can understand the doublespeak of this first line: Caius is certainly not what he seems, and though Kent—as Caius—is honest about wanting to serve the king faithfully, he deceives Lear through his disguise.
In Act 3, Scene 4, Lear and his compatriots are in dire need of some shelter from the storm. Kent discovers a hovel on the heath, and the Fool heads in to make sure it is empty. Unbeknownst to them, Edgar—disguised as Poor Tom—has also sought shelter in the same spot, leading to a moment of dramatic irony:
Fool: Come not in here, nuncle; here's a spirit. Help me, help me!
Kent: Give me thy hand. Who's there?
Fool: A spirit, a spirit! He says his name's Poor Tom.
Kent: What art thou that dost grumble there i' th' straw? Come forth.
Edgar: Away. The foul fiend follows me. Through the sharp hawthorn blows the cold wind. Hum! Go to thy cold bed and warm thee.
By now, thanks to Edgar's soliloquy, the audience is well aware of his disguise as Poor Tom. Shakespeare leverages the dramatic irony available to him through the revelations of soliloquy to privilege his audience over his own characters and prepare them for the chaos to come as the Fool, Kent (disguised as Caius, who is half-mad), Lear (going mad), and Edgar/Poor Tom (pretending to be mad) share their shelter. Yet again, Shakespeare uses clothing and disguise to alter the identities of his characters and stoke the tensions of the plot along.
By blinding Gloucester, Shakespeare creates fertile ground for dramatic irony, as the audience will always have more information than Gloucester can visually perceive. Shakespeare makes use of this situation on numerous occasions, including to almost humorous effect when Edgar leads Gloucester to the “cliffs of Dover” in Act 4, Scene 6. Edgar is supposed to help the Earl take his own life by guiding him to the cliff's edge, but Edgar opts to keep him on flat ground instead. When Gloucester makes his "leap," Edgar acts as though his father has miraculously survived a massive fall:
Edgar: And yet I know not how conceit may rob
The treasury of life when life itself
Yields to the theft. Had he been where he thought,
By this had thought been past. Alive or dead?—
Ho you, sir, firend! Hear you, sir? Speak.—
Thus might he pass indeed. Yet he revives.—
What are you, sir?
Gloucester: Away, and let me die.
Edgar: Hadst thou been aught but gossamer, feathers, air,
So many fathom down precipitating,
Thou’dst shivered like an egg; but thou dost breathe,
Thy life’s a miracle. Speak yet again.
Gloucester: But have I fall’n or no?
By tricking Gloucester into thinking that he has survived a dramatic attempt at suicide, Edgar is able to convince him that the gods hold him in their favor. For the fallen Earl, who remained faithful even at the moment he believed he would die, this must seem a divine miracle. To the audience, however, the scene is decidedly more somber. Well-meaning or not, Edgar’s manipulation of his father’s faith is just another example of the continued subversion of authority—divine or not—that pervades King Lear.