Fortune cookies will occasionally generate in gold vaults, containing money-based rumors.

The player is able to do some sort of ritual that involves sacrificing 25,000 gold pieces to open a portal to Fort Ludios if one has not already been generated. Possibly this would have to be done in a vault. If a naturally generated portal does already exist, the gold is still expended but the attempt to make another one fails.

There is some ritual you can do that allows you to manually create the portal to Fort Ludios. It requires the sacrifice of at least 10000 zorkmids, possibly some special item that is only generated somewhere below Medusa, and that you be in a vault. If the portal to Ludios already generated, this will always fail (it won’t make a second portal).

If a guard is killed in a vault, immediately respawn all the walls of the vault. (Any creatures on the squares where walls are being rebuilt get displaced off them to nearby squares.)

Vaults on deeper levels have walls that take multiple digging actions to dig through, like shop walls do.

Vaults with undiggable walls. You must teleport into them. (The guard will appear inside the vault and teleport you out once you drop your gold.)

Vaults on deeper levels may generate with four gold golems instead of four gold piles. Or both.

Digging through a vault wall counts as 5 tiles (for digging time or wand of digging purposes), and dulls your digging tool’s enchantment by 3.

Single-level branches whose portals, found in vaults, disappear after one use; they are subdivisions of the Magic Memory Vault, and modeled after ADOM “vaults”. These are basically challenge levels, smaller and less rewarding than Fort Ludios (the master branch), that contain some nice loot and harder-than-usual monsters. Portals to them can also be found in vaults in Gehennom.