Mechanus

In the cosmology of the Planescape campaign setting for the Dungeons & Dragons fantasy role-playing game, Mechanus, also known as Nirvana to primes, is the Outer Plane where the souls of people of Lawful Neutral alignment are sent after death. Mechanus is home to the mysterious modrons, who represent the epitome of law and order in the Planescape world.

Mechanus is composed of gigantic cogs that float in space, intersecting at all angles and directions. Some disks are gigantic, stretching many miles across and home to several major cities, while others are no more than tiny islands in a sea of continents. Usually smaller cogs bunch up with larger ones; these are called knots. These knots, are, for all intents and purposes, a single layer. There are many layers on Mechanus; a short listing is provided here:

1. Regulus is the greatest of Mechanus' layers. This layer is home to the modrons, whose strict hierarchy goes all the way up to Primus, who is a greater power. Petitioners are rare on Regulus.
2. Anu is ruled by Anu. This layer is composed of a single disc, upon which rests his palace.
3. The Jade Palace is home to Shang-ti, Celestial Emperor. His palace is the focal point of the Celestial Bureaucracy, which also supervises the Chinese pantheon. The Great Library resides on this layer.

Regulus is divided in an orderly fashion. The layer is divided into four quarters, ruled by the Secundi. These are in turn split into sixteen regions, ruled by the Quartons. Finally, the regions are further subdivided into four sectors, ruled by the Octons.

The gears themselves are guarded fiercely by the gear spirits that reside within them.