D&D General The cosmology of your homebrew campaign


5e Freelancer
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?
There's actually a new spell for this in Tasha's Cauldron of Everything: the Dream of the Blue Veil. It requires that you have something from that world, but does allow you (and some willing creatures that you want to bring along) to travel from your home world to different worlds of the D&D multiverse.

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Follower of the Way
The cosmology, as understood by the region the game is set in, followed by known errors/omissions the players have discovered. Many names are in the local tongue, and might be known by other names in other lands.

  1. Al-Duniyyah, "that which is near/lower," the realm where all mortals live. Functions much as one would expect, with seasons, eclipses, celestial bodies visible from its surface, etc. It is understood by the dominant Safiqi religion to be a place of testing, which is why it can be a dangerous and hostile place, but also a place of great beauty, hope, and love.
  2. Al-Akirah, "that which is far/extreme," the realm from which elemental power appears to arise. A parallel world that matches the loose, but not precise, geography of Al-Duniyyah. Long ago, the genie-rajahs left the (local) mortal world, and began living full-time in this "elemental otherworld." Jinnistan, the genie-country in Al-Akirah, is an incredibly opulent land...assuming you're among the nobility.
  3. Al-Barzakh, "that which separates," frequently just called "the spirit world." Very closely resembles the physical world of Al-Duniyyah, but is shaped by the concepts, behaviors, and beliefs of both sapient mortals and natural phenomena. Dead souls stay here, temporarily, before passing beyond the circles of the world. In theory, every world has its own "Al-Barzakh," but they all go by the same name.
  4. Al-Jana, "the heavens," meaning the celestial sphere above/outside Al-Duniyyah's atmosphere. Little is known about its specific details, as it cannot be physically reached but can be observed. Astronomers and astrologists study it regularly. Exactly why it is physically impossible to exit the atmosphere of Al-Duniyyah remains unknown.
  5. Jannah, "True Heaven/Paradise," claimed to exist by the Safiqi religion, but unreachable by any except those who die and pass on from Al-Barzakh. It is not possible to communicate with, observe, or call back any soul that has departed from Al-Barzakh, so evidence of Jannah is lacking, especially since celestials are not known to exist (at least by current-day mages.)
  6. Al-Jahim, the Underworld, a place of darkness and dangerous things. It seems to brush against the seams of reality and many strange and nasty things can come from its depths. In the deepest pits, the darkness gives way to fire that cannot be quenched--few return from any journey that goes deep enough to see it.
  7. Ja'hannam, "Hell/the Abyss," the place of punishment. Its denizens are either Devils or Demons, allegedly those cast out by the One, the Great Architect, long ago when they broke the divine commands of their Maker. Access to Ja'hannam is difficult at best and always dangerous because of the nature of its residents, but those residents often seek dealings with mortals for (often symbolic) power.

The above are all the planes as known to Waziri mages and Safiqi priests (with Jannah not formally recognized by many Waziri, or only given lip service to avoid religious censure). The Kahina--shamans and druids--do not particularly care much about cosmology and therefore only really care about Al-Duniyyah and Al-Barzakh, and maybe Al-Akirah since elementals come from there.

The party has since learned, however, of at least two planes NOT present in the above list--and the possibility that there are actually infinitely many planes. One is the artificially-constructed "perpendicular" plane of Zerzura, the White City, the Garden-City, built eons ago by the Shi, a race of very alien but incredibly beautiful elf-like beings. It was heavily damaged by the Song of Thorns, a parasitic/mimetic-virus spirit of savagery and entropy, but the party has destroyed that spirit and established a colony of (effectively) the region's first Aasimar, who are interested in repairing the plane--and, if the vision of a possible future holds true, one day the Shi will return and Zerzura will be a place of beauty and knowledge once again, but this time kinder and gentler than before.

While in Zerzura, they came upon a planetarium-like building, in which they discovered a projector that could show the geography of what appear to be other worlds, worlds never catalogued or discovered by the Waziri. If these really exist, it would imply that the Waziri have somehow been deceived, as many, many centuries of magical and physical observation have failed to discover even a single other plane besides the list above. Zerzura itself is obviously one exception, but its "planetarium" appears to imply the existence of hundreds, perhaps thousands of other planes.

The other thing the party has discovered is that there used to be a population of ancient elves living to the south of their homeland (the Tarrakhuna) in what is now called the "elf forests," who called themselves the El-Adrin. These El-Adrin were capable of wondrous and shocking feats of magic, but departed the world long ago for some pocket-plane, because of an as-yet-unknown cataclysmic event which would have prevented their civilization from continuing as it was. They left a few people behind to "begin the return" when the time was right, and those people are the ancestors of the modern elves, somehow diminished from what they were during the time of the El-Adrin. The El-Adrin apparently also had contact with actual celestial beings, including angels and couatl. All the party knows about the cataclysm the El-Adrin fled from is that it was caused by Azimech al-Saqqit, "the uplifted and fallen one," whose coming "changed the world" and would have meant the end of their civilization.

I have already spoken at length about what the party discovered about the origins of devils and demons in other threads, so I'll be brief. All three parties (mortal representatives of the One, the devils, and the demons) agree that long ago they were "servants" like what are now called celestials, but some "rebels" defied the divine commandment to never coerce mortals into following the divine plan. This precipitated a War in Heaven which was infinitely long for those who fought in it and instantaneous to the outside universe. Three factions eventually came out: the loyal Servants, the rebellious Devils, and the anarchistic Demons. Devils believe they won a provisional victory, earning the right to prove that their method of iron laws that cannot be defied is right. Demons believe they won the right to blow naughty word up as much as they like and to whet their unending appetites and unquenchable thirsts via the mortal world. The Servants (and thus, presumably, the One) believe they won the war, giving just and ironic punishments to the Devils (who are now coerced by law just as they wished to coerce others) and Demons (who are now ruled by the very passions they decided to indulge).

The party has also had limited contact with an actual celestial being (a couatl named Tlacalicue, literally "Daylight-Her-Skirt"), or partially-sanctified but still fully "natural" beings (a gold dragon, masquerading as a dragonborn priest, named Tenryu Shen, "Shen" being his given name as he comes from the Asia-inspired Yuxia, far across the western sea.)
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I base my cosmology loosely on Norse mythology with non-human gods pulled from various sources, mostly Greyhawk. In addition, I threw in a bit of Celtic mythology with the Archfey that live in Alfheim, repurposed a couple of worlds and voila. Yggdrassil, the tree of life connects all 9 worlds. I tried to stay true to the spirit of the mythology, but several things are modified. I'm not too worried about it because we only have tiny, tiny scraps of the real mythology and even that is from somewhat unreliable narrators.

In any case, we have 3 levels.

The first level:

  • Asgard, world of the Aesir
  • Alfheim, land of the Sidhe (feywild)
  • Dwarfheim, Land of the dwarven deities
  • Vanaheim, land of the Vanir (Elven Deities)
The second level:
  • Midgard, Mortal Realm (middle world/garden)
The third level:
  • Jotunheim, Land of the giants (Jotuns) and fiends (devils/demons)
  • Svartalfheim, Land of the drow, the underdark
  • Helheim, Realm of the dead
  • Niflheim (shadowfell), World of the dead, shadow and dreams.

The gods of the elves became the Vanir who long ago made war with the Aesir, gods of the humans. Frey and Freya are Vanir, and frequently worshipped by half elves. Since dwarves and dark elves are quite muddled in what little record we have I just repurposed Muspleheim (moved it to Jotunheim) for the dwarves and created Dwarfheim for the dwarven gods. Alfheim is basically the feywild, the Nifleheim is the Shadowfell.

Some of the legends have been tweaked as well. Moradin created Thor's hammer Mjollner and Odin's spear Gungnir. Garl Glittergold wove Sif's hair because even a gnome knows a practical joke can go so far.

So, no great wheel. No plane of air or fire which I always thought was a bit goofy. If you really, really want more detail you can always go to my wiki pages I've built over the years in Obsidian Portal: Thraes Mythology. It is, and probably always will be a work in progress. I don't really expect people to read it all, it's more of a reference for me.

P.S. I promised the link to @Matrix Sorcica long ago in a thread far far away. Sorry I kind of forgot about it!


Okay I tend to use something simpler, such that each setting forms a min-multiverse within the greater whole. Aeons (not too dissimilar to Theros deities, minor cosmic beings) reside over the afterlife.

Deities are relatively minor beings such that it allows mortals to beat them (although they are not too dissimilar to DCEU Olympians), such that even gods can die.

Planes (Branes): They float on the sea of possibilities (or Sea of Brahma), like leaves. These can be from solar system to galaxy sized, of which there can be trillions, or more. All of these alternates has another existing alongside it. They all have their own mythic beings, and afterlives – some of which are positively grim. These can be separated into Fantasy, High Fantasy, Horror, Science Fiction etc.


I use a variant of the great wheel, I suppose, though I never really think of it as such.

There's lots of different planes. Each element (air, earth, fire, water, magic) has one. Each alignment other than pure Neutral has at least one. Each major sentient species has at least one as an afterlife plane. Technically there's still the positive and negative planes as well though I think the last time I used either of these was about 1988. And there's a nigh-infinite number of relatively tiny demi-planes, along with - of course - the prime material and all the many worlds therein.

Tying most of these together are the astral and ethereal planes, along with a few other nodal connectors (e.g. a couple of nexus points, the infinite staircase, etc.).

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?
That is not how I rule it. To get to other worlds in my Prime you can teleport or take a spaceship/spelljamer

That's pretty cool. I haven't really considered other material planes for my setting, but having the fiend's mention them is cool, sort of leaves it open. Have they actually consumed these worlds or are they trying to sow doubt in the minds of the current material plane inhabitants.
Probably, which is why there are so many of them ("them" being fiends in the interest of clarity), but I actually don't really know for sure. Or, I suppose I should say I haven't decided yet?
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(he, him)
My homebrew world Pelhorin has its own cosmology, although it is distantly linked to the great wheel and other cosmologies so that stuff is there should I need it. Anyway, the local cosmology:

The main plane on which people live is known simply as the World. Close to the World is the Otherworld, which is home of spirits and fey, and also the Skies. Leaving the atmosphere of the world by different means accesses a different Sky (one Sky is a crystal sphere floating in phlogiston, another is more-conventional space with giant glowing balls of helium fusion). Each Sky has its own sun, although they are usually all in the sam place so it looks like a single sun when viewed from Pelhorin - sometimes they separate slightly, which is a significant event.

Orbiting the World are six EDIT: probably 12 planes which have an influence on the world when they are close: The Grey is the realm of the dead. The Green is a realm of life; of plants, animals, and wilderness. The Barrens is a battleground, where natives fight it out and other factions from across the worlds occasionally join in. Anarch is a realm of railing chaos, and conversely Concord is a plane of perfect order.

Tieing it all together (in various combinations) are the transitive planes: The Umbra is a plane of shadow and the Radiance is a plane of light. The Ethereal is ghostly realm of mists. All three have “near” regions, which abut the Word and other planes, and deep regions that allow travel between them. All three are four dimensional. Morphea is a realm where dreamers go when they dream, it connects to all planes that have inhabitants capable of dreaming.

The Astral is both a transitive plane and the home of the gods (and a good many other creatures). Within it float Astral Domains, subplanes with their own rules and characteristics, the majority of which are claimed by a god or a pantheon thereof.

Beneath it all are the 13 Hells, home of deamons (more in the Warhammer sense than the D&D sense).

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Goblin Queen (She/Her/Hers)
I love the complexity of the Great Wheel as I love Planescape, but really liked the 4e addition of Shadowfell and Feywild, which are way more interesting than the Positive and Negative plane, although the plane of Shadows is really interesting in itself. After that, the only part which I dislike are the para- and quasi-elemental planes, there are phenomenons happening near the borders, but for me they don't really create new planes. furthermore, although the concept of calling the Astral Plane "the Astral Sea" is interesting, I prefer the original concept, especially since I like Spelljammer as well, which can give enough of a "sea" vibe. :)
I like the Astral Sea because in my setting Melora (the earth/nature/sea goddess from 4e) is the World, very much like Gaia in Ancient Greek mythology. But she’s more associated with the sea than the land, so you get the Worldly Sea and the Astral Sea. And you can kind of think of the relationship between Melora and her children the spirits as analogous to that between the Astral Sea and the Celestial Gods. In fact, those who worship the spirits of nature (mostly druids and wood elves) often contextualize the Celestial Gods as very powerful spirits of the concepts within their divine domains.

There is not elemental planes like the classic D&D cosmology. There are zones like planets or "bubles" within the caothic elemental limbo. The fire plane would be more like a compilation of demiplanes created geothermic heat as renovable energy source, better than coal or petroil and more eco-friendly. That "fire" would be more electromagnectic light, a hot place, but not too much for exploration and colonitation by special magic factions.


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?
I hadn't even considered that we don't really have anything to skip from world to world. Teleport without error used to do this but I guess that doesn't exist anymore.

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