D&D General The cosmology of your homebrew campaign

[Jack Daniel]

My settings' cosmology is analogous to a layered onion, with the "centermost" plane of existence being a static realm of pure Law, and the outermost void a churning sea of Chaotic everything-and-nothing-all-at-once. The planar "layers," from innermost to outermost, are:

The Empyrean Center of All Being
The Platonic Astral Sea
The Inner Etheric Plane (which gradually becomes the Realm of Faerie as one approaches the Material Plane)
The Prime Material Plane (itself a multiverse containing all extant physical universes)
The Outer Etheric Plane (which starts with the Veil of Shadow, which is the realm of the dead, and then gradually fades into…)
The Surface of Limbo
The Void of Chaos

An idea held by some sages — none know whether it's true or not — is that all reality was once one single physical universe, spawned out of the Void by a random quantum fluctuation that became the first Big Bang. Within this universe, some intelligent life-forms evolved and eventually (over countless eons) mastered physics and even transcended mortal limits, only to discover that their vast universe really was nothing more than a tiny, unstable droplet of reality floating in a howling Void of unreality that could perhaps swallow the universe back up in an instant if the proverbial dice ever happened to fall that way. (Think, false vacuum decay.) And so these ascended mortals began to work "outwards" from their fragile reality, creating layer upon layer of stable existence in order to act as a "buffer" between their original universe and the Void — thereby preserving themselves and their original plane of existence. Thus did these transcendent beings, long ago descended from ordinary evolved mortals, become the Creator-Gods of Law.

But as reality became more stable, Chaos began to fight back, and to spontaneously spawn intelligent entities of its own — demons and Chaos Gods, which are essentially Boltzmann Brains (possible because they come from a realm not bound by space, time, or anything vaguely resembling thermodynamics). These entities are wholly dedicated to destruction and entropy, and they encroach constantly on Lawful reality, always trying to help the Void of Chaos swallow existence back up again.

Side note: just for yuks, the planes between the Center and the Void are "shaped" like higher-dimensional platonic solids. The Astral Sea is a hypertetrahedron, the Inner Etheric is a hypercube, the Physical Multiverse is a hyperoctahedron, the Outer Etheric is a hyperdodecahedron, and Limbo is a hypericosahedron — perhaps because some fundamental law of reality required the Gods of Order to build the planes that way in order to keep them stable.

 

[DeviousQuail]

Some of these are really interesting and I will be stealing ideas for the future. In my current cosmology every prime material world is a planet somewhere in the same universe. Look up at the night sky from Homebrew World A and you can potentially see the star that Hombrew World B revolves around. Each of these worlds has some degree of connection to the Ethereal and/or Astral.

The Ethereal is the place where potential starts to find form. It is effectively infinite and home to places like the elemental planes, feywild, shadowfell, demiplanes, etc. There are well-trodden roads, secret paths, and winding trails connecting these realms. Knowing these ways is how most creatures traverse between the prime worlds. One can also head off the ways and into the Deep Ethereal. When done right you can skip all the in between points and move directly to wherever you want within the Ethereal. When done wrong you get ripped into pure potential matter and are lost to the Ethereal entirely.

The Astral is the opposite of the Ethereal. Matter and magic become more static which is why beings here don't age or need to eat. It isn't completely in stasis though so things can be changed. It just requires power and will to do so in contrast to the Ethereals need for power and will to keep things from degrading back into potential. The Astral is shaped like a very crowded solar system. All planets connected to the Astral sit in a large flat disk that revolves around the Astral Star. The more connected a planet is to the Astral the closer their proximity to the star. Most homes for the gods and afterlifes for souls sit in between the planets. It certainly takes on a more space fantasy vibe compared to the Ethereal.

 

[Minigiant]

In my other setting, the comsology is based on Earth's real Cosmos. Also the planes are the gods.

• Solan the Sun and God of Light
• Hegia the 1st Plane of Fire and Goddess of Trickery
• Vegia the 2nd Plane of Fire and Goddess of Love
• Gia the Plane of Earth and the Mother of Life
  • Green the Fey Moon and Goddess of Nature
  • Red the Abyssal Moon and God of Demons
• Megia the Plane of Iron and the Goddess of Battle
  • Diablos the Hell Moon and God of Devils
  • Yama the Hell Moon and Other God of Devils
  • Odin the Vahalla Moon and God of Manlikes
  • Dragon the Dragon Moon and God of Dragons
• Zugia The Plane of Air and the Goddess of Winds
• Sagia The Astral Plane and the Goddess of Time
  • Yellow the Forge Moon and God of the Forge
• Ugia The Heavens and the Goddess of Peace
• Nepia The Plane of Water and the Goddess of Storms
• Hades the Underworld and Goddess of Death
  • Persephone the Elysium and God of Nature
• Centaur the Far Realm of Mutants and Hoofed Star Chaos God of Change
• Minotaur the Far Realm of Freaks and Horned Star Chaos God of War
• The Beast of the Beastlands and Star God of Instinct and Passion
• Hadar the Void and Maw Chaos God of Hunger

 

[Grakarg]

My current homebrew has a pantheon embodied by seven gods. These dieties are the same ones worshipped by all the sentient races with religions, and often have names specific to those cultures and traditions, but are in fact the same divine beings.
The divinities encompass both the positive and negative aspects of their portfolio, so a god of creation is also the god that causes destruction, the god embodying war has militant priests as well as diplomats working for peace. The intent was to have a simple group (seven gods) but have tension and nuance that can lead to conflict for stories. That necromancer cleric you're hunting down? He's part of the same church as the Life Cleric in the party, he just believes he's enacting his god's divine will. How will the cleric in the party react when he learns this?

The Seven in turn are served by a plethora of lesser divine beings who usually champion one aspect of their god and are more active in the world at large. This is the the group of beings that fuel a Warlock's dark pact for example, or might appear in a Paladin's dream asking for aid, etc. Both Celestials and Fiends work to further the aims of the gods. An angel might reward or protect the faithful, and a pit fiend might work to tempt the weak or punish those who've failed the gods. They might even work together for specific aims (like Crowley and Aziraphale from Good Omens) It always creates a bit of a shock for the players when a powerful devil shows up and helps them out.

Demons on the other hand operate outside the auspices of The Seven and create chaos for its own sake or have their own goals. They might create cults among the mortal races that all good worshippers of the seven should work to stamp out. This is to set up situations where previous adversaries of players could find common cause and perhaps work together with them when the need aligns.

All in all, its an attempt to have stuff both ways. A simple pantheon for the Players to use to create characters but still allow me as a DM to create whatever adversary or complication I want to have as needed.

Typically for the classes with a religious bent, the Knowledge Religion skill becomes pretty important.

 

[Minigiant]

I forgot the "best" part of my Solgia cosmology.

Since the planes are gods and most of them are single females, if you seduce a single goddess you can create a demiplane-demigod child to place your stronghold on.

And since one is basically Gender Swapped Zeus, high level fighters and CHA casters often have their own demiplane.

 

[glass]

There's lots of different planes. Each element (air, earth, fire, water, magic) has one.

This reminds me, it looks like I missed elemental planes our of my previous post. My original writeup had a single Elemental Chaos-type plane called The Maelstrom a one of the orbiters, but that does not really work so well with the "orbitting planes influence the World" thing that I shamelessly stole from Eberron have going on. But OTOH, how many/which elements exist is a thing that different cultures disagree about on Pelhorin

Which leads me to a question as to how you lot rule on something: I've always allowed the spell Planeshift to take you from one prime material world/setting to another (e.g. Greyhawk to Toril) in the same universe, even though technically you're still on the same plane. Why? Because otherwise there's no spell that can jump you from world to world. Am I alone or unusual in this ruling, or is this how others handle it as well?

Interesting question. I would not allow you to plane shift from Greyhawk to Toril since they are in the same plane (the Prime Material). As written (at least with the PF1 version), you could do it with two castings, but I might consider houseruling that now that I think about it.

Things are slightly more complicated with my own setting, since the World is in a sense a separate plane from the Skies (with the Skies effectively being alternate Prime Materials - or at least part thereof), but in another sense is in all of them. On balance, I would not allow plane shift from Pelhorin to a Sky, but I would from one Sky to another (locally, anyway).

Plane shifting directly from Pelhorin to Acheron in the GW would be possible, but would be more difficult than just casting the spell normally. Depending on the system it might require a feat and/or some kind of check, and it would definitely need a more elaborate focus than the usual tuning fork.

Mine tends to be Great Wheel (although it actually forms a shell around the multiverse, largely protecting it from the Far Realm)

Do you have another plane "opposite" the Outlands to make a complete sphere (or hypersphere I guess)?

 

[Lanefan]

In my current cosmology every prime material world is a planet somewhere in the same universe. Look up at the night sky from Homebrew World A and you can potentially see the star that Hombrew World B revolves around.

This!

 

[DeviousQuail]

This!

I like it for many reasons but mostly because it's simple. The universe is mind bogglingly vast so I'm not going to run out of room for my worlds. I even put my scifi stuff in this cosmology.

 

[Scott Christian]

I use this:

The realms are ethereal. No one can "visit them" They are just floating objects in the solar system that seem to have an unnatural ability to cross paths with the world of Allor. The people of Allor have developed special telescopes to be able to spot and track some of the realms. Others, remain a mystery as to when they touch.

And touching is the problem. The elemental realm caused a hundred-year storm one time when it just seems to stick to Allor. All the realms have created the creatures of Allor; from sirens to giant spiders, from demons to dryads, from efreet to zombies. Some swear adventurers are people touched by the Supernatural realm.

The realms also brought magic to the world. The people of the world only have elemental magic under control. The other magics are either shunned, and therefore not studied, or studied and caused terrible situations. For when the realms come into contact with people, it seems to change them - most of the time in a bad way.

I use this cosmology to explain the creatures of the world. I use it to explain the magic system. I also use it to explain the old religion, still practiced by the dwarves, northfolk and wilders. And lastly, I use it to "possibly" explain a PCs uncanny ability to live, when most normal people would die.

 

[jmartkdr2]

Start with the wheel, but subtract the planes of conflict. I think its enough to have the basic 8 of LN/LG/NG/CG/CN/CE/NE/LE based, then have Ethereal, Astral, Fey, Shadow. I dont have a Positive/Negative planes, but source I guess, like background energy.

I think on top of the Far Realm you also need a Plane of Dream, I dont really understand why thats not more of a thing, but I guess some of its tropes get eaten up in Fey/Shadow Planes.

I go a bit further: I have three-ish sections in the outer planes:

1. The Upper Planes. Most sit 'behind' Mt. Celesita, across the Astral Sea. So you must go past the guardian angels to get to them. They don't really have a map, they're just a bunch of places for good gods and good souls to reside. Reaching them without passing the guards is nearly impossible.

2. The Abyss. Again, not really mappable, just a bunch of layers that may or may not really be on top of each other. All sorts of fiendish things live here: demons (tanarii, mariliths), rakshasa, slaadi, demonic beastfolk, yugoloths, weird undead, night hags... if it's a fiend and not a devil, it's around here somewhere.

3. Acheron and Hell. Hell sits in the middle of the plane of conflict, which is spotted with hives of fiending insects (chasme, xill, et al), and the devils and their infernal beast pets reside in the middle behind a massive wall.

4. Mechanicus is around here somewhere as well, but it's small enough to be overlooked, and there's room for other stuff.

I do use the Blood War, to explain why these entities aren't more involved in the material plane. Most of the fighting happens in the Abyss (demons hate everything, including other demons) and Acheron (demons want it destroyed as well), with occasional assaults on Mt. Celestia. The downside of this setup is it means gods are either rather distant or somehow not the main forces in the outer planes - I'm okay with this but it means clerics need some tweaking.

The inner planes overlap: it's really one big plane, kinda like the Elemental Chaos, but bog sections dominated by one element are pretty common.