Alternate Primes
by Bruce PierpontPerhaps the concept of alternate primes mould work better. Not alternate Prime Materials, alternate primes. So the layout of the planes would look something like:
| Inner Planes | Prime Material | Outer Planes |
| Blackmoor's Inner Planes, possibly shared | the Blackmoor prime | Blackmoor's outer planes possibly shared again |
| Mystara's Inner Planes, possibly the same as the other world's inner planes. | Mystara/Nightmare as described in Set 5 No crystal sphere's exist here | Mystara's Outer Planes Including the planes of the various Immortals |
| The AD&D "Big Three's" Inner planes, possibly shared with other primes | The "Big Three": Toril, Oerth, Krynn in their crystal spheres. | The standard Planescape, MotP Outer Planes |
| Athas' Inner Planes Possibly shared with "Big three" | Athas | Athas' Outer planes Possibly the same as the "Big three's" |
| Any other set of Inner Planes, possibly shared | Some other world (Alphatia, Averoigne) | Possibly another set of Outer Planes |
| the Ethereal | the Astral |
Possibly there is more than one
Ethereal or Astral, but from what I hear of Planescape it suggest
one ethereal and one astral connecting the "Prime Material" to the
"Outer Planes" and "Inner Planes", which may be composed of
different areas depending on which set you visit. So Odin only
exists once as a God, and maybe once as an Immortal because his
Outer plane is connected to all primes that worship him. I could
write more if I gave it more thought, but I'd like to check for
contradictions from published sources first.