Acheron is one of the Lower Planes. It's law- and evil-aligned.

Characteristics

Acheron is composed mostly of complete vacuum (much like outer space) with giant iron cubes floating through it, each of which has its own breathable atmosphere.

Planar traits

• Objective directional gravity (on the exterior of cubes, down toward the surface; on the interior, usually down toward any interior surface)
• Divinely morphic
• Mildly law-aligned

In Acheron time passes at a different rate the farther you get from your own personal entry point.

Layers

• Avalas?
• Ocanthus?
• Tintibulus?
• Thuldanin?

Inhabitants

• demons?
• the rilmani
• the maugs?
• steel predators?

• Azrashak?
• The Iron Triad
  • Zorayan
  • Karayan
  • Arakel

Locations

• The Forge of Cycles? — an ancient cube, 50 miles across, currently held by Vladislav Chernovsky?, and also (formerly) inhabited by Ileana?; meetings of the inner circle of the Cult of Loki are held here
• The PCs' base — a medium-sized (~2 miles across) cube, held by Nikolai and used as the party's primary base of operations
• Azrashak's cube? — a continent-sized cube (one of the largest known), once the domain of the demon lord Azrashak?, now unclaimed by any one power or entity, but infested with many factions of demons and other creatures
  • contains a library?