Chest of the Forlorn Conqueror

Chest 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 Robes
 * Mercurial Vestment
 * Reinforced Sapphirium Battleplate
 * Reinforced Sapphirium Breastplate
 * Reinforced Sapphirium Chestguard
 * Shadowflame Robes

Source
This item drops from Halfus Wyrmbreaker in the Bastion of Twilight on Heroic mode.

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