Ashjra'kamas, Shroud of Resolve

Ashjra'kamas, Shroud of Resolve, is a cloak crafted by Wrathion. As part of end-game progression, it can be upgraded 14 times by completing a time-gated quest chain involving completing objectives in Horrific Visions. Each new rank will provide better stats and better protection against sanity loss. New appearances are unlocked at rank five and twelve.

Source
The item is a quest reward from Beginning the Descent.

Upgrades
Wrathion will offer quests asking players to enter Horrific Visions. As a reward for completing his quests, Wrathion will offer upgrade items for the cloak. This involves a time-gated quest chain. The first quests up to Stepping Through the Darkness were offered week one, then an additional quest was offered each week after that.

Bonuses
As the cloak increases in rank, in addition to the straight stat and item level bonuses, the cloak also picks up some bonus effects:
 * Rank 6: Updated appearance and new on-use effect:
 * Rank 12: Updated appearance and new equip effect:
 * Rank 12: Updated appearance and new equip effect:

Trivia

 * It was named Experimental Blacktalon Shroud during early PTR.
 * The name Ashjra'kamas could be a reference to the Asarakam, the Dragon's Kin, a race of dragon-like aberrations from the manga Claymore. Also, the word Asāraka means "Void" in Sanskrit.