At the boundary between the Nine Hells and Mechanus, in the Outer Planes, lay the plane known as Acheron or the Acheron Plane.
The ruby red of the Nine Hells and the diamond blue of Mechanus mingled into a strange, dark purplish red, evoking unease and an urge to flee.
The Acheron Plane was divided into four layers, one above another.
They were Avalas, Thuldanin, Tintibulus, and Ocanthus.
Each of Acheron's four layers was different.
First, as for its overall structure, the Acheron Plane had infinite space, but no vast, boundless land.
The space of Acheron was filled with countless floating cubes that bore life.
The enormous cubes were like one floating island after another.
Each cube was the size of a small plane, and some of the largest were even comparable to a Medium Plane.
All kinds of life lived on these cubes.
Some were undead from the Prime Material Plane, while others were native life from the Outer Planes. There were even some creatures from the Nine Hells and Mechanus.
The First Layer of the Acheron Plane, Avalas, was the most densely populated.
The black-and-gold cubes were home to countless creatures, as well as countless souls who had been judged worthy of coming to Acheron after death.
Boundless numbers of souls formed nations on the surfaces of the cubes according to their faith and alignment, and fought for control of them.
Some cubes, meanwhile, were occupied by different deities.
Nishrek and Clangeddin were the most famous among them.
Orcs and Dwarves waged an eternal war across these two territories.
Other deities also held territories of their own on various cubes.
On some unclaimed cubes, Devils and Lesser Demons could be found. The demon forges from Mechanus also mined these cubes to replenish and repair the gears of Mechanus.