Edgar is interrupted by a gentleman who enters carrying a bloody knife. The messenger explains that Goneril, before committing suicide, confessed that she had poisoned Regan. The gentleman also relates that Regan is now dead as well.
Edmund realizes that he has lived his life foolishly and maliciously. He hopes to do one act of goodness before his death, so he tells the Duke about the letter ordering the execution of Cordelia. But Edmund is too late.
Edgar goes off to find the captain and stop him from killing Cordelia. But when Edgar returns, he is with Lear, who comes in carrying the dead body of Cordelia.
The distraught old king grieves desperately, but he is no longer mad. Lear explains that he killed the man who had hanged Cordelia.
Kent, who appeared some minutes earlier (at line 228), grieves with Lear and reveals his identity to the old king. As Kent and Lear stare at each other,
Kent asserts …
If fortune brag of two she loved and hated,
One of them we behold. (279-80)
They are beholding each other, and Kent is declaring that in earlier times they experienced good fortune (the love of Fortune), but in more recent times their experiences were negative (her hate). Fortune or Fate is thus once again described as an entity or force that acts on a whim and is inconstant in her favors.
Man cannot trust Fortune.