Why did Shakespeare insert the conflict between Goneril and Regan over Edmund?
In the last scene of the play, Goneril confesses to poisoning her sister Regan and then commits suicide herself. The crux of the conflict begins in Act IV, when a "love" affair emerges between Goneril and Edmund. At the same time, upon learning of the death of her brother-in-law Cornwall, Goneril immediately suspects that the widowed Regan will try to supplant her as Edmund's lover. In the first scene of Act V, Goneril's jealousy leads her to exclaim that she would rather lose the battle at hand than see her sister get Edmund. The insertion of this odd love triangle into the plot of King Lear is intended to intensify the animal-like viciousness of the two women. Their cooperative endeavor against their father and Cordelia is a matter of sheer expediency. In the end, Goneril and Regan are so irredeemably evil that they cannot keep their unholy alliance together. Neither displays true passion for Edmund, each would rather deny satisfaction to the other than to realize a perverse love affair with the bastard.