Ser Mandon Moore was a member of the Kingsguard for Robert Baratheon and Joffrey Baratheon. Jaime Lannister remarked that he was its most dangerous member as one could never tell what he was thinking. He had no personal life and only lived for duty.

During the Battle of the Blackwater, he attempted to kill Tyrion Lannister (believed to working under Cersei Lannister's orders), succeeding in cutting off a portion of his nose. Tyrion was saved by his squire Podrick Payne, who slew Moore by pushing him into the water, where the weight of his armor dragged him down.