From Rich Green’s intro post:
Imagine Mike Mearls has given you the job of coming up with the #dndnext cosmology. What would you keep from prior editions and what would you bin?
I was kindly invited to join in the blog carnival after my Planescape post; thanks Rafael! So, as to the question above, my answer to the question of what would I keep from previous editions is “very, very little.”
OK, that’s not entirely accurate. I’d still have demons, devils, elementals, fey, Sigil, and Spelljammers. There’s be plenty of other ideas carried over as well, I’m sure. But my framing of it all at a high level would be very different from previous editions. Instead of the classic “Great Wheel” model or the “World Axis” of 4th Edition (about which I honestly know very little), I would present a basic overview of the multiverse similar to the Snowflake/Bleed model of Warren Ellis’s Wildstorm comics.
Basically, there are an infinite number of universes, each of them infinite in itself but also connected by an equally infinite extradimensional space. Let’s say that extradimensional space is the Astral Plane or Astral Sea. It permeates all universes and also exists outside of them. Travelling the Astral Sea, most commonly by means of a Spelljamming ship, is how one can travel between any of these universes. Some universes are so similar in function and form that everyone has the same name and similar lives, save that all of the good guys have goatees and are evil. Some universes are incredibly alike in function, but not in form (the Forgotten Realms, Eberron, or Greyhawk).
But there are some universes that function in completely different ways, and sometimes these universes “bump” up against each other in the Astral Sea and stay that way for an unfathomably long time. If the beings from one of these universes are powerful enough relative to the beings in one of the others, then they are perceived as gods.
This super-macro view of reality would only be vaguely guessed at by the most mindblowingly brilliant sages in the most advanced of D&D settings. The view from the ground, so to speak, remains largely unchanged. Maybe in the Realms, the Great Wheel model dominates scholarly thought, whereas in Sigil the multiverse is seen as an infinite city. This brings me to another point, though — what does the cosmology of my “default” D&D setting look like?
I would actually use a pretty basic dualist approach, as that works quite well with the mythology-oriented functions of the rules (clerics, undead, etc.). There’s a Heaven blessed by the Divine Light, guarded by angels and attended to by saints and prophets. There’s a Hell damned by the Infernal Darkness, littered with imps and lorded over by demon and devil princes. There be a realm of Faerie/Feywild and something like the Shadowfell would exist, and it would be quite possible to wander into them by accident and not realize until it’s too late. The Shadowfell would be a sinister realm of heightened horror that appears much like the “normal” world, à la Ravenloft. The Underdark would have a bit more of a mythic underworld vibe. The most important thing is that it’s simple and lightweight; leave the heavy exploration of multiversal theory for the supplemental material.