King of the Mountain
From Tolkien Gateway
The King of the Mountain also referred to as the King of the Dead,was the king of the traitorous Men of the White Mountains, who had sworn allegiance to Isildur in the War of the Last Alliance. For breaking his oath, Isildur cursed him and his people to walk the Paths of the Dead until they could redeem themselves, which they achieved by aiding Isildur's heir Aragorn II in the War of the Ring.
