The Army of the Dead

The Army of the Dead was created from former Men of the Mountains who broke their oath and became restless spirits for thousands of years until Aragorn as Isildur's heir promised to free them from their oath-bound unrest if they aided him in defeating the Corsairs of Umbar laying siege to Pelargir.

Led by King Rioc, the Army of the Dead were not the only grouping of spirits to rise in the wake of Aragorn's passage. The Ruthless Dead led by Drugât refused Aragorn's call for aid and continued their worship of Sauron, staying behind in the Paths of the Dead to threaten the passage of any living mortal.