|Dead or Alive||Dead|
At the end of the Second Age, their king, known as the King of the Mountains, pledged allegiance to Isildur at the Stone of Erech. However, these Men later refused to aid Isildur in his war against Sauron; they came to the aid of neither side, but instead hid in the mountains. They had previously worshipped the Dark Lord during the Dark Years. As punishment, Isildur cursed them, saying that they would not have peace or rest till they fulfilled their oath upon his command or that of his heirs.
Their spirits haunted the caverns beneath the Dwimorberg, the Haunted Mountain, and the valley of Harrowdale that lay in its shadow—though they were said to appear in the valley only in times of trouble or death, haunting the hill of the Stone of Erech.
Malbeth the Seer prophesied that a day would come when need and haste would drive one of Isildur's heirs to take the Paths of the Dead and that the Dead would answer to his call. Thousands of years later, in the final years of the Third Age, that prophecy was fulfilled. In the War of the Ring, Aragorn, Isildur's heir and direct descendant, called upon the Dead, summoning them to the stone of Erech, and commanded them to fulfil their oath and be free. On this occasion, he first uses the royal banner of Gondor, made by Arwen and delivered to him by Halbarad and the Grey Company; and in the film, delivered personally by Elrond.
They followed him through Gondor's lands and fiefs south of the Mountains, and at the port of Pelargir they drove away the Corsairs of Umbar, allies of Sauron. Their oath fulfilled, Aragorn granted them their freedom, and they vanished at last from the world. After this, Aragorn gathered the warriors of the region to him. They sailed to Minas Tirith on the Corsairs' own ships, and saved the day at the Battle of the Pelennor Fields.
The Men of the Shadow Host appeared to be grey shades; some still rode ghostly horses, but all moved at the same speed. They bore swords and spears and banners, and answered a horn-call with their own horns. However, they did not need weapons (it is left vague whether they and their weapons are "material" at all), for their primary weapon was fear.
In the battle with the Corsairs, as recounted by Legolas and Gimli to Merry and Pippin, the Corsairs abandoned their ships in terror, which Aragorn then commandeered; those who did not flee drowned in the sea. In fact, they terrified Mordor and Gondor's soldiers alike (as they passed through the land, people hid in terror, and they even disrupted a local battle).