Treasury refers to the treasure vault of the Great Tomb of Nazarick.
During Ainz Ooal Gown's golden years as a PK guild and at the peak of its power, the guild amassed a vast fortune of gold and spoils from their conquests and adventures in YGGDRASIL. All of this wealth would later be interned and stored within the Treasury for safekeeping. Its construction and design were handled by Genjiro and Tabula Smaragdina.
The Treasury does not appear in the directory of the floors of the Great Tomb of Nazarick, and could be considered a separate floor by itself in Nazarick. It exists in a separate spatial plane that can only be accessed using the Rings of Ainz Ooal Gown.
Furthermore, every treasure Ainz Ooal Gown owns or acquires through the guild's various activities has its respective place in the Treasury. Treasures of importance are kept in different categories, ranging from armors, weapons, jewelry, auxiliary tools, consumables, manufacturing goods, etc. This makes them easily accessible to guild members.
In addition, within the Treasury lies the Nazarick maintenance room and data crystal storage room both extremely important places.
The entrance to the Treasury begins at the Treasure Hall, a gallery that contains a limitless ceiling and is literally filled with mountains of treasure. While the enormous quantities of gold and luxurious items may appear staggering, the items placed here are considered to be of little value compared to what is locked further in the vaults.
While so, flying is the only way to cross the mountains of gold effectively towards the gate that leads into the deep recesses of the Treasury. The "Blood of Jormungandr" an unknown item, produces a poison cloud that renders the surrounding air highly toxic to prevent thieves from trespassing. If one does not possess any abilities or tools capable of countering this toxicity, they would drop dead within three steps.
The Door to the Treasury
[“With great sagacity it doth ascend gently from Earth to Heaven. Again it doth descend to Earth, and uniteth in itself the force from things superior and things inferior.” ~Holmyard, Alchemy, p.95]
On the other side of the chamber was a recess in the wall, that is in the shape of a door, but looks like a bottomless pit. The door could only be opened by a predetermined password. Though perhaps with high level magic or a special skill from the rogue class, one could force their way through this door.
When each member of Ainz Ooal Gown began to silently retire from YGGDRASIL, every one of them relinquished possession of their personal items and weapons to Momonga as throwaway. The Mausoleum was built by him in honor of those guild members, and acts as a special shrine to them. While all of the guild members' personal equipment are stored here, the great golden stone statues known as Avatara equip those items in their likeness as an honor to them.
Avataras are golems who act as the guardians of the guild members' relics they're equipped with. Additionally, the mausoleum has a special defense mechanism that will only activate should a ring bearer of the Ring of Ainz Ooal Gown were to enter its range or premises. The golems will then awaken and attack the ring bearer, using the very weapons formerly possessed by the guild members of Ainz Ooal Gown. Therefore, one must enter without having on a Ring of Ainz Ooal Gown in order to bypass the activation of the final defense mechanism. Past this place is where Pandora's Actor dwells.
- The Mausoleum was originally named as the Innermost Sanctum of the Treasury, but Momonga renamed it and re-purposed it, in memory of his comrades.
- According to Ainz, he had only come here when paying for the upkeep costs of Nazarick with the money he had earned, and that had been years ago before his arrival in the New World.