The Plane of Shadow
The plane of shadow is a transitive plane, existing in the same space as the Material Plane. Everything that is in the material plane shows up in the shadow plane, but with one major difference.
Everything in the shadow plane is a dull, colourless version of the material plane. A plane of only black, white and grey. Fires still give warmth, but not the warming glow one would be used to. Everything appears slightly hazy, as if seen through slightly blurred eyes, and looking into the distance is a difficult task.
The main central room of The Karrick Lancers’s planar stronghold exists in the Plane of Shadow, the entrance to which sits on the Material Plane, hidden in a grubby looking shack in the middle of a vast bog on the continent of Orhaven, far away from prying eyes.