Neltharion's Vault

Neltharion's Vault is a large cavern found in Highmountain, accessed through the Path of Huln. It was here that the drogbar fitted the goblin-made plates to Deathwing. Stored here was the Hammer of Khaz'goroth and two sets of titan disks in a small chamber accessed with a Titan Waygate. With the help of Igrul the Scalebane, Huln Highmountain used the hammer to banish Deathwing to Deepholm.

The Slave Enclave leads to Obsidian Overlook, which lets non-dragons escape by flight path.

During the third invasion, Mayla Highmountain, Spiritwalker Ebonhorn, and adventurers entered the cavern as part of tauren tradition and learned about the history of Huln.

• Conjured Defender
• Titan Defender
• Obsidian Reclaimer

• Treasures of Deathwing (vignette)
• Echoes of Deathwing (bonus objective)

• Burning Plate of the Worldbreaker, which unlocks the Last Breath of the Worldbreaker appearance for the Protection Warrior's Scale of the Earth-Warder artifact, can be found in the piles of gold coins.
• Before patch 7.3.5, The Grey One could be found at the end of a long path full of Goldsnuffle kobolds.
• In the beta, lying forgotten in corners of Neltharion's Vault were a Dragon Soul Experiment, Expended Orb of Domination, and Mantid Sonic Tower that were all removed before launch.
• During the beta, Brann Bronzebeard was planned to appear here, trying to uncover a treasure, as well as Baine Bloodhoof. Time-Lost Slaves, Time-Lost Whelps, Vault Guardians (charred skeletal dragons), and Echo Batlings were also present.

This may be the lair where Neltharion hid the Demon Soul during the War of the Ancients.

It is extremely likely that this is a section of Neltharion's Lair.