If you unlock an epic quality chest at the end of the Delve run you also need a special key to open it - Treasure Trove Key. This epic chest is available once you have completed a Tier 8 or higher Delve.
You can get Treasure Trove Keys from:
Renown
Reaching Renown 24 from the 4 Renowns in The War Within rewards Treasure Trove Keys.
World Boss
A World boss will be active in one of the 4 zones each week. The World Boss has a chance to drop Treasure Trove Key.
Weekly Quest
The Weekly quest "Delves: Khaz Algar Research rewards a Treasure Tove key once you complete 3 delves in a specific area.
This quest is found in Delver´s Headquarter´s in Dornagal, Isle of Dorn. THe questgiver is Brann Bronzebeard,
Other posts
- Exciting New 12-Month Subscription Package from Blizzard
- The War Within Weekly Dungeon Event: Complete 4 Dungeons for a Heroic Nerub-ar Palace Loot Cache!
- New Severed Threads Nerub-ar Palace Buff Now Active – Enjoy 2.25% Bonus Damage and Healing!
- Maximize Your Weekly Gear in WoW's 20th Anniversary Event
- Comprehensive Guide to Bronze Celebration Tokens in WoW 20th Anniversary
- Transform into Iconic Warcraft Characters in 11.0.5 20th Anniversary Event
- Mists of Pandaria Classic?
- Kamala Harris Faces Backlash Over World of Warcraft Stunt
- Understanding Xal'atath's Bargain: Devour and the Void Rift Debuff
- The War Within: A Major Shift in Tinderbox Economics