What is the fateful end of King Lear's three daughters?

All three of King Lear's daughters meet their demise in the final act of the play. Goneril and Regan both die at the hand of Goneril; Regan begins to display symptoms of illness until eventually she declares that her "sickness grows upon me," and she exits the stage. Later, Goneril too exits, and it is afterwards revealed that Goneril has killed herself, having admitted that it was she who had administered poison to her sister. The tension between the two women had escalated over their mutual lust for Edmund, who was, as he says, "contracted to them both."
As soon as the sisters are dead, Albany, Goneril's husband, is eager to know the whereabouts of the king and Cordelia, who had in fact been sent to prison. Albany sends to have them released, not knowing that Edmund had previously commanded the guards to kill them. Unfortunately, he is too late —Cordelia has already been hanged in her cell; although, Lear has killed the guard who did this.