King Hagon Hoare, also known as Hagon the Heartless, was a King of the Iron Islands from House Hoare.
Hagon took the throne when his older brother, Harmund III Hoare, was dethroned and mutilated by the Drowned Men, led by the Shrike. He quickly expelled the Faith of the Seven from the Iron Islands. He allowed the Shrike to mutilate his mother, Queen Lelia Lannister, and then return her to her family home of Casterly Rock. Her outraged nephew, the King of the Rock, responded by invading the Iron Islands.
Ser Aubrey Crakehall, a commander of the Lannister armies, would defeat Hagon on Great Wyk during the seventh year of fighting and would capture Hoare Castle. Before being hanged, Hagon was mutilated in the same way that his mother had been.