Goneril is Lear's eldest daughter. After professing her deep love for her father and receiving half of his kingdom, she betrays him and plots his murder. Goneril's expressions of love are extreme and reveal the inherent dishonesty of her nature. Goneril reveals her true character when she defies the hierarchy of nature, which calls for daughters to respect and honor their fathers, and lays the groundwork for the torment she will set in motion for the remainder of her father's life.
Goneril leads her father to believe that her love for him extends beyond any evidence of poor behavior, and so ultimately, she is responsible for Lear's actions, having earlier endorsed them. Later, both Goneril and Regan are depicted as especially cruel and bloodthirsty, as they call for Gloucester's punishment. Throughout most of the play, having power has been most important to Goneril, but by its conclusion, she is willing to lose the battle, and thus the kingdom, rather than lose a man.