On their way to the Instant Fortress, Eckmond had shared much knowledge about the owners of this fortress, the Doomguard.
The Doomguard is one of the many factions in Mark City, and speaking of Mark City, one must explain the structure of the multiverse.
To put it simply, there are three types of planes in the multiverse: the Inner Layer, the Prime Material Plane, and the Outer Layer. Their current location, the Bottomless Abyss, where Demons live in the Nine Hells, and the Barrens where Mark City is situated, all belong to the Outer Layer.
As there is an Outer Layer, naturally, there is an Inner Layer. The Inner Layer consists of various elemental planes, including the Earth Elemental Plane, Fire Elemental Plane, the plane of Positive and Negative Energy, etc. The base materials of the world indeed originate from the Inner Layer, while the Ether Realm connects the Inner Layer with the Prime Material Plane.
