Gristlegrim's Dungeon Levels
The complex is divided into 6 levels with 9 rooms on each level arranged in a 3 by 3 grid. Each room is numbered with the first number indicating the level of the dungeon. As you can see, there are a lot of rooms in Gristlegrim.
The rooms are generally about 100 feet cubical--that is 100 feet on each side and 100 feet high. The walls glow with a dim light equivalent to twilight or pre-dawn--delvers can see all right, but things can be dim. The walls are impenetrable to any substance or magic known on Trollworld--at least anything short of god-level magic cannot affect them. You can't mine, melt, phase through, or destroy the walls of Gristlegrim. No matter how many doors a room may have leading in and out, only one can be open at a time.
Anything can happen inside these rooms. It may appear to be a simple room, or a whole world may be placed inside it. The wizard Khazan was trapped inside a world inside Gristlegrim for a hundred years back before the rise of Lerotra'hh, the Death Goddess.