King of the Dead, also known as King of the Mountains or Dunharrow King is a Lord of the Rings minifigure who appears in LEGO The Lord of the Rings: The Video Game. He will be released as a physical minifigure in August in the set 79008 Pirate Ship Ambush. He has a glow-in-the-dark head.
In the later years of the Second Age, he and his men also served and worshiped Sauron, until he and his army found Gondor. Isildur was the King of Gondor at that time. The King of the Dead made an oath to fight on Isildur's side when Isildur needed him. But when Isildur needed him most he did not come. Isildur cursed the King of the Dead and his army. Then the King of the Dead could not rest until his oath was fulfilled. In The Return of the King, the king and his army fought with Aragorn and the Grey Company at Pelargir. There they defeated the Corsairs of Umbar and an army of Haradrim. When the battle was over and Aragorn, as the Heir of Isildur, told the Army of the dead that the oath was fulfilled, and with the rest of his people, "vanished like a mist that is driven back by a sudden wind," never to be seen again.
In Peter Jackson's film adaptation of The Return of the King, and in LEGO The Lord of the Rings: The Video Game, the King of the Dead and his army help Aragorn, Legolas, and Gimli-the Grey Company does not appear-to seize the Black Fleet of Umbar, and then take the ships to the Pelennor Fields. There the Army of the Dead emerges and helps to destroy the forces of Mordor invading Minas Tirith, at which point Aragorn holds their oath fulfilled and releases them.