Oathbreakers

The Oathbreakers were the shades of Men of the White Mountains. The Men of the Mountains, whose King swore allegiance to Isildur and the Dúnedain in the last years of the Second Age. They had worshipped Sauron in the Dark Years before the foundation of Gondor, and when the time came for them to fulfil their oath, and fight beside Isildur against their ancient master, they broke their word, and hid in the mountains. Isildur cursed them to survive without rest until their oath was fulfilled. Waiting for Isildur's heir to appear and grant them the chance to fulfil their word at last they haunted the caverns beneath the Dwimorberg, and the valley of Harrowdale, also known as the Paths of the Dead, that lay in its shadow, though they were said to appear in the valley only in times of trouble or death.

In the War of the Ring, Isildur's Heir, Aragorn, called on the oathbreakers to fulfil their oath at last. They followed him through the Gondorian lands south of the Mountains, and at the port of Pelargir they drove away the allies of Sauron in fear. For their aid, Aragorn granted them their freedom, and they vanished at last from the world.