Mechanus is a single-layer outer plane of Lawful Neutral alignment extending infinitely in each direction. The plane is filled with an immense clockwork machinery that never ceases to tick. The abstract calculations performed by this machine are impossible to comprehend, even for greater powers such as Banor or Asmodeus. A typical cog in the machine averages 500 miles across. Each of these massive metallic disks is largely flat and has its own gravity. This gravity does not affect other nearby cogs, so the disks can meet perpendicular to each other without disturbing their function or the creatures on their surface. Gravity also works normally on the obverse face of a cog, but it is rare that two opposite sides are both occupied.
All of this is representative of the true nature of Mechanus: a plane of absolute order. It is the home of Otonor the Lost and Primus, the chief Modron.
Localized Phenomena
It is impossible to deceive someone with illusions or phantasms on this plane. Spells that produce these effects function, but the illusions are obvious to observers.
Flying over the edge of a cog and falling results in the traveler floating in a manner similar to the Astral Plane, with a slight tug towards nearby planes.
Optional Rule: Law of Averages
While on Mechanus, creatures always use the average damage result for attacks and spells. For example, an attack that normally deals 1d10 + 5 damage always deals 10 damage on Mechanus.
Optional Rule: Imposing Order
At the end of each long rest taken on this plane, a visitor that is not lawful neutral must make a DC 10 Wisdom saving throw. On a failed save, the creature’s alignment changes to lawful neutral. The creature’s alignment reverts to normal after one day spent on a plane other than Mechanus. Casting the dispel evil and good spell on the creature also restores its original alignment.
Fauna and Flora
Only the Modrons are native to this plane.
History
Primus is often sought for advice by greater powers, since he is a powerful Lawful Neutral deity. He is not immortal, however, and the highest-ranking Modron immediately assumes his role, portfolio, and name should he ever be killed or destroyed.
Notable Locations
The Palace of Divinity and Verdanthalla are located within Mechanus.