Oathbreaker

The Oathbreakers also known as the Dead Men of Dunharrow, were a Pre-Númenórean people, originally settling in the White Mountains who were cursed by Isildur to never find rest until they fulfilled their oath of allegiance to Isildur and to fight against Sauron.

They haunt the Paths of the Dead, a haunted passage under Dwimorberg, the Haunted Mountain, in the White Mountains connecting West Rohan to Western Gondor. After Aragorn and the Grey Company passed through the Paths of the Dead, and summoned the Oathbreakers to the Stone of Erech, many of the Dead, but not all, followed him to Pelargir. Those who chose to remain behind still trouble various parts of Western Gondor.