The Citadel of the Arcane is a mysterious fortress built into the lower reaches of the Spine of the World mountain range on Oerth. It is the only settlement of The Arcane on Oerth. The Citadel is the ultimate destination of the Dresium Road that snakes all across Oerth. Caravans bring their loads of dresium to the Citadel and in turn receive valuable gold and jewels from The Arcane.

The groundlings of Oerth do not know the purpose of the Citadel or The Arcane, but of course the spacefaring races know that this settlement collects dresium for processing into spacejamming helms on the asteroid settlement of the Rock of Bral. How the dresium is transferred from the Citadel to the Rock is a mystery to all as The Arcane use no ships.

The Citadel itself is a giant block of light bluish color wedged into the mountains. From a distance it looks almost like a very geometrical square glacier. It has no obvious means of entry or exit. When The Arcane leave it, circular portals open and then quickly close up.