Сharacter level 120.
We recomnned this service to farm gear with corruptio and lvl up your cloak Ashjra'kamas, Shroud of Resolve.
Also you can loot Corrupted Memento from visions: Full clear - 1300-1600, Full clear with 5 masks - 4500-5200
If you'll unlock all talents in your legendary cloak, then you can buy these items from Wrathion:
Vessel of Horrific Vision - farming service by daily quests and Visions of N'Zoth Assaults in Uldum and Vale of Eternal Blossoms.
Leveling 1-15 for Ashjra'kamas, Shroud of Resolve - ETA 3-4 weeks
Legendary back unlock - ETA 1-2 hours.