Chest of the Forlorn Vanquisher

Chest of the Forlorn Vanquisher is a tier 11 armor token. It can be exchanged at in Stormwind City or  in Orgrimmar for the following items:
 * Firelord's Robes
 * Magma Plated Battleplate
 * Magma Plated Chestguard
 * Stormrider's Raiment
 * Stormrider's Robes
 * Stormrider's Vestment
 * Wind Dancer's Tunic

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