D&D General What Does Your Cosmology Look Like?

[Lanefan]

A multilayered sphere, like onions or Russian nesting dolls. The world has 15 layers, 7 heavens, 7 hells, and the place in between, where mortals live. I liked Eberron’s division into Khyber the Dragon Below, Eberron the Dragon Between, and Siberys the Dragon Above, but felt the fact that Eberron had both the Orrery planar system and the Khyber system felt a bit redundant. So I figured it could be interesting if my setting’s cosmology worked as a sort of synthesis of Eberron’s two cosmologies.

The 7 Hells are the different layers of the inside of the planet. The ocean is the first hell (very Cthulhu-esque), the second is the Underdark (with spooky undead stuff), the third is the world’s mantle/Plane of Fire, and so on. Each layer of the world is ruled by an Archon, a demonic tyrant that helped create the world and is linked to one of the seven deadly sins. At the center of the earth is Yaldabaoth, the lion-faced serpent god of creation, pride, and tyranny.

Really cool. Like it!

Were I to adopt this the only big change I'd make would be to somehow make it less centered on the one planet, such that it could instead be universal and thus applicable to all worlds. So, instead of being modelled on an onion or Russian doll, it would probably end up resembling a stack of pancakes or a many-floored building, with the game's planet on a middle layer along with all the other planets and worlds.

It would be easy to have both models in play at once, though: the universal actuality is the pancake layers but the game world's occupants see it as the onion.

The 7 Heavens are the layers of the world above. The sky/realm of clouds is the first heaven, then the planet’s rings, then the Moon, then the Sun, and so on. Each is the domain of an Aeon, a distant, transcendent good god that embodies the virtues of humanity: Love, Wisdom, Individuality, Justice, Light, et cetera. The final heaven is the Astral, the domain of Abraxas, the redeemed rooster-headed, snake-legged Archon of dreams, prophecy, fate, magic, and redemption.

Question: other than the Planeshift spell, are there any means of connection and travel between these planes similar to the Infinite Staircase, or is there a planar nexus somewhere? I ask because that's often the role of the Astral plane, which here has become its own discrete layer.

 

[Lanefan]

Unspecified in detail because I want it to be a) not a focal point b) be mythological and unexplained. Having a specified cosmology and telling it the players would make it explained and "scientific".

Nothing says you have to tell it to the players.

If they're interested anyway, maybe let them discover bits of it slowly as the campaign goes along.

IME having a nailed-down cosmology right up front sure helps from the DM side, even if the players never see it or learn about it.

 

[W'rkncacnter]

i haven't really run my own proper setting, so normally i just use whatever cosmology the setting im using has, but i had ideas for a couple different campaigns...that i haven't finished. but here's what i got...

the cosmology of the first was that there were basically only two planes - the material and the astral. the material is basically an infinite material plane, with all the functions of the elemental planes baked into it, while the astral is a sort of "noosphere" that embodies the thoughts of those in the material so that people weren't just spawning stuff with their minds willy nilly. this is important for the concept of the campaign and development of the setting. the astral always existed, but the material was made by two primordial beings of time as essentially a cosmic game of whose philosophy was correct and thus whether creation was worth any sort of effort.

as the campaign went on, the various cultures on the material would invent their own religions based off their histories and legends and such, and the beings from these religions would see life in the astral, where they'd form their own divine realms and hells and such. eventually something would happen to shatter the barrier between the astral and material, the various beings in the astral sea would descend into the material to attain land and followers and whatnot, and the players would have to find a way to stop them from accidentally killing all life in the crossfire, possibly shattering the universe into a new cosmology in the process.

the other cosmology was a lot simpler and less developed and honestly not so much a cosmology as it was a single plane. it was basically a hollow earth type deal with gravity that worked more like a ringworld that was formed by gods tearing out various pieces of different material planes and binding them together into an enclosed fortress world to keep those pieces of planes safe from outside forces. this would have been easily visible because the cuts were hasty and many of the transitions not smooth (e.g. you might have a mountain with a nearly entirely flat side where it was cut, or an ancient ruin underground might suddenly end and lead into a volcanic cave system). the core of the planet would have been a floating portal with its own gravity to some other plane (i never decided which one) that would slowly rotate to create day and night. and...that's about as far as i got.

EDIT: i forgot that the first cosmology also had godlike beings be created on the material whenever a new concept became possible (e.g. one of the first adventures would have been a mass combat between the players and their people vs a force trying to destroy them, which would have been the first war ever conducted, so a being of war would have spiraled into existence during the fight). i never developed the setting enough to figure out a way to make this make sense, though, so it's just kinda...there, i guess.

 

[Levistus's_Leviathan]

Really cool. Like it!

Thanks!

Were I to adopt this the only big change I'd make would be to somehow make it less centered on the one planet, such that it could instead be universal and thus applicable to all worlds. So, instead of being modelled on an onion or Russian doll, it would probably end up resembling a stack of pancakes or a many-floored building, with the game's planet on a middle layer along with all the other planets and worlds.

It would be easy to have both models in play at once, though: the universal actuality is the pancake layers but the game world's occupants see it as the onion.

Yeah, most cultures across Earth believe they live at the center of the universe, so the cosmology was designed to reflect that. My setting is disconnected from the Planescape/Spelljammer-style world-hopping or interaction with other D&D settings. Those that prefer otherwise could definitely reshape it to a flat cosmology as opposed to spherical one.

Question: other than the Planeshift spell, are there any means of connection and travel between these planes similar to the Infinite Staircase, or is there a planar nexus somewhere? I ask because that's often the role of the Astral plane, which here has become its own discrete layer.

Physical travel is the most common method of moving between the planes. Swim into the ocean and you're in the First Hell. Walk into any deep cave, and you're in the Underdark. Fly into the clouds, and you're in the First Heaven. Every plane physically bleeds into the next, and there are places where they merge. Xibalba, a flooded section of the Underdark, is where the First and Second Hells meet. Volcanoes connect the Plane of Fire to the surface world. But each transition between layers has unique challenges. Good luck getting through the Plane of Fire without immunity to fire damage.

The Ethereal is the main transitory plane in my setting, and you can relatively safely travel up or down the cosmos through the Deep Ethereal.

And there's also the World Tree, which I envision as basically being the supporting structure for the planet. Its colossal trunks function as a highway, of sorts, across the cosmology. The Yggdrasil stretches all the way from the core of the planet (where its seed was planted) up to the Astral, where its canopy scrapes the stars.

 

[Lanefan]

Good luck getting through the Plane of Fire without immunity to fire damage.

I kinda suspect that's true of everybody's Plane of Fire.

Ditto, good luck getting through the Plane of Water without some means of breathing the stuff.

And there's also the World Tree, which I envision as basically being the supporting structure for the planet. Its colossal trunks function as a highway, of sorts, across the cosmology. The Yggdrasil stretches all the way from the core of the planet (where its seed was planted) up to the Astral, where its canopy scrapes the stars.

So one could move from plane to plane by finding and then climbing up and down Yggdrasil? If yes, that's cool too!

 

[Retros_x]

Nothing says you have to tell it to the players.

If they're interested anyway, maybe let them discover bits of it slowly as the campaign goes along.

IME having a nailed-down cosmology right up front sure helps from the DM side, even if the players never see it or learn about it.

When I dont tell it to players, why should I write it at all I never had any moment where I had the feeling I am missing a cosmology to run my games. When I need a plane of existence or some other cosmic concept I introduce it. Schroedingers cosmology is how I use it. But it rarely comes up anyway, because I rarely run higher-tier adventures with plane hopping. No one of my players do actually care where the fire elemental was summoned from, and neither do I.

 

[Levistus's_Leviathan]

So one could move from plane to plane by finding and then climbing up and down Yggdrasil? If yes, that's cool too!

Exactly. Or inside it’s hollow trunks and roots.

 

[SkidAce]

Exactly. Or inside it’s hollow trunks and roots.

Brilliant.

scribbles notes
...isolated dome towns, is the Infinite Staircase in here?, cavernous tree tunnels, twisting maze roots, tree mining?, underdark cave to root transition, literal river branches...

 

[W'rkncacnter]

When I dont tell it to players, why should I write it at all

because if something related to it comes up you'll already know how it works?

might not be a concern for cosmology specifically but the principle is still there

 

[TwoSix]

because if something related to it comes up you'll already know how it works?

might not be a concern for cosmology specifically but the principle is still there

I think the disconnect here might be that it's quite possible to know how something works, often in great detail, without actually documenting everything.

I have a ton of "notes" about my game setting and my cosmology, as an example, but it's all just saved in the meatware. Nothing is written or saved to a file.