Leggings of the Forlorn Conqueror

Leggings of the Forlorn Conqueror is a tier 11 armor token. It can be exchanged at in Stormwind City or  in Orgrimmar for the following items:
 * Mercurial Leggings (heroic)
 * Mercurial Legwraps (heroic)
 * Reinforced Sapphirium Greaves (heroic)
 * Reinforced Sapphirium Legguards (heroic)
 * Reinforced Sapphirium Legplates (heroic)
 * Shadowflame Leggings (heroic)

Source
This item drops from Maloriak in Blackwing Descent on Heroic mode.

It can also be purchased from the following vendors for :
 * in Stormwind City
 * in Orgrimmar