|Vault of Mhuvnak|
Sometime after the Alessian Slave Rebellion, various Ayleid kingdoms launched a desperate search for the fabled Wrathstone, a weapon that they believed would be their salvation against the encroaching forces of the Alessian Empire. An expedition marched to the Dwemer city of Mzulft, in the hold of Eastmarch in Skyrim, where it was rumored the Wrathstone was held. The Ayleids besieged Mzulft, but failed to breach it or retrieve the artifact. At the time, the Ayleids were unaware that the Dwemer only possessed the left half of the Wrathstone, and that half was stored not at Mzulft, but at nearby Kagrenzel. The famed Dwemer architect Mhuvnak left Mzulft for Kagrenzel immediately after the attack to retrieve the artifact, realizing that it may need to be better guarded. It is thought that he found the defenses of Kagrenzel inadequate, and built the Vault of Mhuvnak to house it instead. Long after the time of Mhuvnak, following Mzulft's temporary fall to the Nords and subsequent reclamation by the Dwemer, the Vault of Mhuvnak was buried in a mountain of ice and lost. The Dwemer of Mzulft attempted to use their Oculory to locate the "Frostvault", but no record of the results of their search was found, and the left half of the Wrathstone was not reclaimed.
In 2E 582, the frozen entrance to the Dwarven Vault of Mhuvnak finally thawed, attracting the attention of both the Goblins and the local wildlife. The treasure hunter Tharayya, accompanied by the Undaunted, ventured into the vault and encountered a group of rieklings who now called the Dwemer ruins their home, as well as various functional and dangerous Dwemer constructs. The vaults themselves were locked tightly, and the adventurers had to improvise by using a Dwarven delver to blast open the fortified door of the vault. The Wrathstone's vault was guarded by a Dwarven colossus, which was taken down with the help of some skeevatons. Tharayya retrieved the left side of the Wrathstone Tablet from the vault with the help of the Undaunted.
The glacier covering the surrounding mountains would also cover the entrance to the vault for long periods of time when it froze over. By 4E 201, no evidence was left of the Vault of Mhuvnak being visible to the surface.