The King of the Dead is a supporting character in the third and final novel of The Lord of the Rings trilogy, The Return of the King and the 2003 film adaptation of the same name.
Background[]
The Ghost King's true name has been lost in time and history. Instead he has been known as the King of the Dead. He and his army swore to assist Isildur in Gondor's time of need. However, when the King and his men retreated and did not follow through with their deal to the King, Isildur cursed them into never finding rest until they fulfilled their oath.