Greyhawk Megadungeon Idea

Lately I've been musing over the need for some new megadungeons in Greyhawk. The ones we have are classic and have been revised, returned to and played out for the most part. My personal stab at this is a proposed megadungeon set in the Dry Steppes. The Dry Steppes is a remote, undeveloped area with ancient historical background. For my own amusement this hypothetical dungeon is also set very close to the southern border of Ull, a land that no one knows better than myself. Without further ado, I introduce Qabu Al-Imbraturi "The Vault of the Emperor".

Here is my very rough idea: 

The location of Qabu Al-Imbraturi was lost to memory since the Invoked Devastation ravaged the Baklunish Empire, thus ending their long war with the mutually annihilated Suloise Imperium. Nomads of the Dry Steppes had traveled in the shadow of this ruin for generations without ever knowing of its existence, until recently, when it appeared following a brief display of strange lights in the night sky. The upper ruins of this ancient edifice is carved into the side of a mountain while deep below, vast armories and arcane foundries are said to house the most destructive weapons ever crafted by the Baklunish. Sages speculate that escalating warfare upon the Fields of Padyr to the south and grim portents concerning the Suel Mages of Power, forced the Padishah to pour massive manpower and resources into the creation of the Vault. What mighty artifacts and relics were created here is unknown, but surely great elemental magics must be contained here; possibly a precursor to the infamous Rain of Colorless Fire.

At first the ruin's appearance was a curiosity for superstitious nomads; deemed either a holy site or a cursed domain. Before long the lure of treasure and magic attracted less scrupulous foreigners. Based out of the nearby town of Kester, teams of highly competitive explorers have begun to pierce the upper dungeon, after first contending with the natural dangers of the steppes. The full extent of Qabu Al-Imbraturi has yet to be determined due to vicious traps and ancient wards still in place. The lethality of the dungeon has led some parties to share their knowledge in order to make further progress. Despite the risk, it's only a matter of time before some bold, resourceful adventurers discover how to penetrate the deeper levels of the Vault of the Emperor.

(more to come?)

Update 06/19/2021: (Still more to come?)