World vs Plane vs Sphere vs Universe?

[Yakmala]

I've been playing D&D for many years through many rules variations, and it seems like the cosmology of the game universe has shifted over the years. Reading over the new spell Dream of the Blue Veil from TCoE made me ponder the current state of the 5E universe.

If I'm understanding things correctly, and please point out if I'm wrong on this, worlds like Toril, Kyrnn, Eberron and even the MtG worlds that have been brought into 5e, all exist on a single Prime Material Plane in the same universe. But each is contained in its own crystal sphere, kind of like a mini-universe, with some goop in-between called phlogiston that spelljamming ships can travel between to reach different spheres. It's travel between these spheres that Dream of the Blue Veil allows.

So, assuming any of the above is true, I have questions..

1: Are gods/pantheons unique to each sphere? Are they aware of the other spheres? Are versions of the same gods in different spheres their own unique entities?

2: Are the outer and inner planes, places like the elemental planes, the Feywild, the Nine Hells, the Shadowfell, etc, shared by all the spheres? Or does each sphere have their own versions of these planes?

3: Just how big is an individual crystal sphere? Is it galaxy sized or larger (to use modern terms) or is that all an illusion, and they are relatively small, with what we think of as stars just being points of light on the inner surface of the sphere? Do stars, as balls of hot gas, even exist?

4: How exactly does the Ethereal Plane fit into all of this?

5: Is everything described above the "multiverse"? Or is it still just one universe with other parallel universes theoretically existing in 5e?

[PhoenixPhyre]

My understanding of the stock multiverse is basically the same. Although one addition to the pre-numbered stuff--

There are uncountably many versions of each of these worlds, each in an alternate planar set. One for each DM that's ever played a game, maybe one for every individual campaign.

Thus (working from least to most specific):

Multiverse : contains all the versions of the planar structure for all worlds. Very little, if any, communication between these universes.
Universe : A single version, with a single complete set of planes (material, inner, outer).
Crystal Sphere : Those worlds mutually accessible without entering philogiston. As I understand it, this is usually on the scale of a solar system (plus or minus).
World : a single planet within a crystal sphere.

So the answers (as I understand them) to your questions:

1. No...with exceptions. Some are, some aren't. The big boys tend to get worshiped in many spheres, but some of hte smaller ones are individual. Expect wide variation. Often, what's called X in one sphere might get called Y (and worshipped differently) somewhere else.

2. Generally common. Except for off-norm settings like eberron or dark sun (or my own homebrew) that have unique planar structures.

3. Generally the size of a solar system, but, as I understand it, the stars are actually light from other crystal spheres shining through philogiston. Sort of. But messily.

4. The Ethereal connects all the planes within a single planar set (so within a universe). Although 2e said that ethereal travel through the inter-sphere space was difficult. Unclear.

5. All of that is one universe within the set of parallel versions as I understand it. Certain settings kinda break the rules and exist "on their own" with a different set of planar structures. Whether they're part of other material planes is unknown at this time as I understand it.

[Naanomi]

NOTE: My answers are drawn from past edition lore (mostly 2e/3e, along with 5e), not just 5e... so take that for what it is.

1: Are gods/pantheons unique to each sphere? Are they aware of the other spheres? Are versions of the same gods in different spheres their own unique entities?
Pantheons/Gods are not unique to each sphere in most cases, many Gods are worshiped on many worlds; and for the most part they all dwell in the shared Outer Planes. There are some exceptions in weird cosmological situations. Still, many pantheons tend to 'keep to themselves' and not get involved beyond their own interests. The Forgotten Realms, for example, have Gods from the Egyptian and Mesopotamian pantheons represented here (that came over with human slaves, presumably from real-world Earth)... a few immigrants from the Celtic pantheon... and of course many of the racial Gods are worshiped in many places on many planes. At least one God born from Aber-Toril (Waukeen) has worshipers on other worlds as well. Note that a God's individual strength varies from plane to plane... a being who may be a Greater God in charge of a pantheon on one Prime may only be a minor deity on another; and their 'real' standing on the Outer Planes may be a mixture of those various influences in some ways.


2: Are the outer and inner planes, places like the elemental planes, the Feywild, the Nine Hells, the Shadowfell, etc, shared by all the spheres? Or does each sphere have their own versions of these planes?
The Inner and Outer Planes are shared for all worlds on The Great Wheel. The Feywild and Shadowfel are individual for each world, but there are hints of a 'Deep Feywild' and 'Deep Shadowfel' that don't correspond to a 'mirror' of the Prime Worlds and are probably shared/connected. A few Prime Worlds are not very well connected to them though... Athas has a barrier (called 'the Grey') that makes travel all but impossible to and from the world, and some interpretations of Ebberon have it 'separated' from the Great Wheel by a series of orbiting demi-planes (if it isn't its own cosmology)


3: Just how big is an individual crystal sphere? Is it galaxy sized or larger (to use modern terms) or is that all an illusion, and they are relatively small, with what we think of as stars just being points of light on the inner surface of the sphere? Do stars, as balls of hot gas, even exist?
Crystal Spheres are very large... Greyspace is 16 Billion Miles across. Most contain a single Solar System; then a whole lot of mostly empty Wildspace before it hits the end. Stars exist, well... suns exist anyways: most spheres have a single hot ball of gas in the center with a portal to the Fire Elemental Plane (or in older editions, the Plane of Radiance) at its center. Other stars... not so much: most are on the wall of the Crystal Sphere itself... giant glowing crystals or enormous lightning bugs or the like... or portals through the crystal sphere... or blurry images of other nearby crystal spheres 'through the wall'... though a few are actually creatures that look like stars (one of the largest beings in existence are those that are 'made' of constellations); and some are actually other planets, planar phenomenon, etc... including the famous 'cerebrotic blots' that are tied to the Far Realm and the Great Old Ones floating around out in the emptyish void of Wildspace


4: How exactly does the Ethereal Plane fit into all of this?
The Ethereal Plane is a transitive Plane, a place 'between' worlds that is the medium that separates the Inner Planes and the Prime Material Plane. It also extends into the 'Deep Ethereal' where other cosmologies besides the Great Wheel may exist. The Astral Plane is very similar, only being between the Outer Planes and the Prime instead. If you really want to get into planar lore, there is a little more to it than that (especially very early in the Great Wheel's history) but... this is good enough for a good understanding.


5: Is everything described above the "multiverse"? Or is it still just one universe with other parallel universes theoretically existing in 5e?
Almost all of everything is contained within 'The Great Wheel', which can be thought of as a giant multiverse of sorts. There are things beyond The Great Wheel though... other cosmologies (Ebberon might be one, authors disagree... Spellweavers come from one as well); things that are connected to but not part of The Great Wheel (the Far Realm being the most prominent, which 'threatens all cosmologies' according to some sources)... and things that exist from a time before The Great Wheel was made (Draeden, some beings from the Plane of Time, the LeShay, the Eldest Ones that theoretically created the Great Wheel and some of their servants, etc). Travel to/from these 'outside' places is not impossible, but beyond the power of even the Gods and with a few notable exceptions can be treated as functionally impossible barring freak accidents.

[KorvinStarmast]

I've been playing D&D for many years through many rules variations, and it seems like the cosmology of the game universe has shifted over the years. Reading over the new spell Dream of the Blue Veil from TCoE made me ponder the current state of the 5E universe.
Multiverse. It's even referred to as that in the core books.

[Unoriginal]

If I'm understanding things correctly, and please point out if I'm wrong on this, worlds like Toril, Kyrnn, Eberron and even the MtG worlds that have been brought into 5e, all exist on a single Prime Material Plane in the same universe. But each is contained in its own crystal sphere, kind of like a mini-universe, with some goop in-between called phlogiston that spelljamming ships can travel between to reach different spheres. It's travel between these spheres that Dream of the Blue Veil allows.

That is mostly correct, although a Crystal Sphere is less a mini-universe and more like a solar system. Basically, it's a bubble of space inside the phlogiston. You can also use a Teleportation spell, but you'd need to know a teleportation circle at the desired point of arrival.



1: Are gods/pantheons unique to each sphere?

Many of the weaker gods have influence only on one sphere, but they're not really *bound* by the sphere.


Are they aware of the other spheres?

Yes.


Are versions of the same gods in different spheres their own unique entities?

All of the versions are the same god, but each version is different based on the kind of influence the god can have, due to the nature of the Sphere and the state of the world.

For example, the drow god on Ebberon is a barely known servant of Lolth on others. Both are the same being, through a different filter.



2: Are the outer and inner planes, places like the elemental planes, the Feywild, the Nine Hells, the Shadowfell, etc, shared by all the spheres? Or does each sphere have their own versions of these planes?

Yes and no. All the planes (except demiplanes) are infinite and shared between the Spheres, but the nature of the sphere modifies the planar influence greatly, and which regions of which planes is connected to which world depends on that. Some of the Crystal Spheres cut off some of the planar influence completely, or distort it in very weird ways.



3: Just how big is an individual crystal sphere? Is it galaxy sized or larger (to use modern terms) or is that all an illusion, and they are relatively small, with what we think of as stars just being points of light on the inner surface of the sphere?

I'm not quite sure about the size, but most of the ones the books focus on are at least big enough to hold a solar system.



Do stars, as balls of hot gas, even exist?

Sure, many stars are like that. Others are eldritch entities floating in space.



4: How exactly does the Ethereal Plane fit into all of this?

The Ethereal Plane is a liminal space between the Material Plane and the Inner Planes.



5: Is everything described above the "multiverse"? Or is it still just one universe with other parallel universes theoretically existing in 5e?

Well 5e does not mention parallel material planes like some other editions do, so as far as we know yes, what is described above is the multiverse.

Although you haven't mentioned the Far Realm, which is also part of the multiverse.

[Naanomi]

Although you haven't mentioned the Far Realm, which is also part of the multiverse.
Though not part of the Great Wheel, which itself is sometimes described as 'a multiverse'... some 3.X lore used the term 'Omniverse' to describe all alternative Cosmologies together, which likely would include the Far Realm (as much as it can be included in anything)


I'm not quite sure about the size, but most of the ones the books focus on are at least big enough to hold a solar system.
"Each sphere varied in size but typically they were twice the diameter of the orbit of the planet that was farthest from the sun or planet at the center of the sphere (the system's primary)". Earth’s crystal sphere would be... 9 billion miles across?

[Unoriginal]

Though not part of the Great Wheel, which itself is sometimes described as 'a multiverse'... some 3.X lore used the term 'Omniverse' to describe all alternative Cosmologies together, which likely would include the Far Realm (as much as it can be included in anything)

True, although 5e implies strongly that the Great Wheel model is just how some mortals choose to perceive/represent the planar interactions, and that it's more widespread than others because it's a popular manner to explains it in Sigil (notable, as the Great Wheel model mirrors the Outlands, where Sigil is, pretty well).

[Naanomi]

True, although 5e implies strongly that the Great Wheel model is just how some mortals choose to perceive/represent the planar interactions, and that it's more widespread than others because it's a popular manner to explains it in Sigil (notable, as the Great Wheel model mirrors the Outlands, where Sigil is, pretty well).
True, and this was true to some degree even in older Planescape stuff ('this stuff can be perceived different ways').

However, I meant the 'Great Wheel Cosmology' not the 'Great Wheel Model' per se... in that there still appears to be things 'outside' the system of planes (the Far Realm, wherever the Eldest Ones live, things predating the modern cosmology, wherever Spellweavers came from, etc)

[Unoriginal]

True, and this was true to some degree even in older Planescape stuff ('this stuff can be perceived different ways').

However, I meant the 'Great Wheel Cosmology' not the 'Great Wheel Model' per se... in that there still appears to be things 'outside' the system of planes (the Far Realm, wherever the Eldest Ones live, things predating the modern cosmology, wherever Spellweavers came from, etc)

I misunderstood what you meant, then. And you're right.

[Millstone85]

How exactly does the Ethereal Plane fit into all of this?As I understand it, there are at least 9 layers to the Ethereal Plane:

the Deep Ethereal
the Border Ethereal

material shore
fey shore
shadow shore
fire shore
air shore
water shore
earth shore
chaos shore


When you are on the Deep Ethereal, all there is to see is grey mist. Sometimes, the mist becomes colorful, which indicates a portal to one of the shores collectively known as the Border Ethereal. The mist turns orange for the fire shore, a pale blue for the air shore, etc., as described in the table page 49 of the DMG.

When you are on the material shore, it is like you were on the Material Plane proper, except that you see everything grey and blurry, are weightless, can pass through walls, and are invisible to most creatures.

When you are on the fey shore, it is like you were on the Feywild proper, except... etc. etc.

Of note is that the chaos shore seems to be the only viable way to explore the Elemental Chaos.

It is not mentioned page 49, but it would be logical for the para-elemental planes to have their own ethereal shores. Anything created with demiplane, or similar magic, might as well.

Also of note is that casting etherealness while in the Astral Plane, the Outlands, or any of the Outer Planes, has no effect. The Ethereal Plane does not "border" those.


Although 2e said that ethereal travel through the inter-sphere space was difficult. Unclear.Yeah, somehow, the phlogiston may not have an ethereal shore, even though it is part of the Material Plane. I guess it is a bit like how, in Star Trek, a ship can't simultaneously use its warp drive and its cloaking device, unless that was retconned out in one of the new series.

[Yakmala]

If, as some are suggesting, the inner and outer planes are infinite and shared by all the spheres, that would mean you could potentially have classes/races/spells and technology from multiple spheres meeting up somewhere like Sigil or the City of Brass and from there, potentially travel back to a world not their own. So you could end up with, for example, a Warforged, Kender or Leonin in Faeurun (Assuming an individual DM allows it).

[Naanomi]

If, as some are suggesting, the inner and outer planes are infinite and shared by all the spheres, that would mean you could potentially have classes/races/spells and technology from multiple spheres meeting up somewhere like Sigil or the City of Brass and from there, potentially travel back to a world not their own. So you could end up with, for example, a Warforged, Kender or Leonin in Faeurun (Assuming an individual DM allows it).
Absolutely, Spelljammer is full of examples of this stuff as well.



Yeah, somehow, the phlogiston may not have an ethereal shore, even though it is part of the Material Plane. I guess it is a bit like how, in Star Trek, a ship can't simultaneously use its warp drive and its cloaking device, unless that was retconned out in one of the new series.
The phlogiston has no planar connections at all, planar travel is impossible (even things like bags of holding are inaccessible)... the souls of the dead even have to find their way to a sphere before going to the afterlife because of lack of astral connections. It is pure 100% unadulterated Prime

[Unoriginal]

If, as some are suggesting, the inner and outer planes are infinite and shared by all the spheres, that would mean you could potentially have classes/races/spells and technology from multiple spheres meeting up somewhere like Sigil or the City of Brass and from there, potentially travel back to a world not their own. So you could end up with, for example, a Warforged, Kender or Leonin in Faeurun (Assuming an individual DM allows it).

Sure, that does happen.

For example, Arkhan the Cruel (who is from Faerun) has spent time on Exandria (in the Critical Role setting) and helped the local heroes to fight Vecna (who is from Greyhawk's world of Oerth) in order to steal the god-lich's hand.

[Devils_Advocate]

I don't think that most of Spelljammer has been updated for 5th Edition yet. But I'll answer based on my understanding of relevant 5E information, previous edition material, and also how I think things should be. To wit:

The thing to understand about Spelljammer and Planescape is that they are, among other things, crossover settings that allow characters to travel between different D&D worlds. Note the "different". Basically, unless there's something about a world that precludes its connection to the crossover setting (in which case it's the world's fault), it's presumed to be connected. And that means that every world has to be sufficiently self-contained that its details don't apply to other worlds, because those other worlds get to be both different and connected. So while there can be multiple worlds in the same sphere with the same laws of magic or whatever, those setting details are still local, just over a quite large region.

This has several consequences:

1. Your gods have no power here.
That old definite article sure is context-sensitive, isn't it? When we're only talking about the world of the Forgotten Realms setting, Mystra is the goddess of all of the magic in the world or something close to it, or such is my understanding. But in the context of the broader multiverse, Mystra is the goddess of all of the magic in a world, or maybe several relatively close ones, but not really all that big of a deal on a cosmic scale. If you pray to Mystra to deal with your magic issues in a sphere where she's unknown and "the Weave" isn't even a thing, she's not even going to be able to intervene on your behalf. If you want divine assistance with something, try asking the locals what deity handles it, and maybe they'll inform you how to direct your prayers productively.

The deities with power in a given crystal sphere are generally the ones that are worshiped there. Many deities are worshiped in more than one sphere. Different cultures may revere different aspects of a deity, but that's true within a single world! The various aspects of a deity probably tend to at least be on speaking terms with one another. I mean, can you imagine sharing a divine realm with an alternate interpretation of yourself for centuries and neither of you saying a word to the other? Awkward...

2. Not every wold has the same planar connections.
The Phlogiston is cut off from other planes. Even the Border Ethereal. Extra-dimensional spaces don't even function. So assuming that the Phlogiston takes up most of the volume of the Prime Material Plane (to the extent that it makes sense to say such a thing about an infinite space, if the Prime truly is infinite...), the general rule for which other planes one can travel to from the Prime Material Plane is none of them.

So planar travel from the Prime always happens from within one of the spheres, each of which is its own self-contained setting that gets to do whatever it wants. It's possible to travel between another plane and multiple spheres, but one will tend to wind up in different places in that other plane. For starters, locations in some planes — the Feywild, the Shadowfell, the Ethereal — directly correspond to locations in the Prime Material, and the easiest method of travel to such a plane generally leaves the traveler in the "same place" in the three conventional spacial dimensions. And it seems clear to me that there pretty much has to be something similar going on with the other planes too.

I mean, come on. Do you encounter an entire different ecology of fire creatures that speak an entirely different language every time that you get sent to a "random" location on the "infinite" Elemental Plane of Fire? More likely you encounter the same civilization of efreet multiple times if you visit often enough. So clearly you keep returning to the same general region, which only makes sense if you think about it. In order to have an equal chance of appearing at any place in an infinite plane, your chance of appearing at any given one would be zero, so you wouldn't even be able to go there in the first place. The math just doesn't work out. So obviously there's a correspondence between any two planes that allow "random" travel to each other, such that one is most likely to appear near a corresponding location and increasingly unlikely to appear at increasingly distant locations.

After all, if Sigil only has a finite number of portals, they only go to a finite number of places on the Prime, which all exist within some finite region of space. Other, vastly distant regions of space are probably linked up to their own parts of the Outlands, their own islands of stability in the Hinterlands, different from Sigil and the Gate Towns.

3. Crystal Spheres can be very weird.
While a typical sphere is roughly the size of a solar system and contains a solar system, they can depart from this model to varying degrees. The world of Greyhawk is at the center of its system, orbited by its sun along with the other worlds despite the sun being bigger. But that's a mild example.

A crystal sphere, solar-system-sized or otherwise, could be half filled with earth and water and half filled with air. Familiar creatures could live on the surface of their flat world, with many stranger things inhabiting the depths below and sky above. The sun could orbit a central point, passing through a massive tunnel at night.

There could be a galaxy-sized sphere out there somewhere, but it would have to be very far from known Spelljammer space in order not to be common knowledge already. Our own observable universe could be in a crystal sphere. Any canonical interaction with our own world could be seen to suggest that. Or perhaps it's more likely that we're in an alternate Prime, accessible through other means.


Just how big is an individual crystal sphere? Is it galaxy sized or larger (to use modern terms) or is that all an illusion, and they are relatively small, with what we think of as stars just being points of light on the inner surface of the sphere?
It's our stars that are an illusion, silly! They look like points of light fixed to the inner surface of a sphere until they're very carefully examined and their trickery is revealed. :P


Do stars, as balls of hot gas, even exist?
There are suns, which may or may not be gaseous. But suns aren't the same thing as stars in Spelljammer, except of course that every crystal sphere is allowed to be different, so maybe sometimes.

[Millstone85]

The phlogiston has no planar connections at all, planar travel is impossible (even things like bags of holding are inaccessible)... the souls of the dead even have to find their way to a sphere before going to the afterlife because of lack of astral connections. It is pure 100% unadulterated PrimeWow, I didn't realize, or I forgot, that it was that harsh!


The various aspects of a deity probably tend to at least be on speaking terms with one another. I mean, can you imagine sharing a divine realm with an alternate interpretation of yourself for centuries and neither of you saying a word to the other? Awkward...I remember 4e stating somewhere that different aspects of the same deity felt really uncomfortable around each other. It probably had something to do with an identity crisis, or perhaps they ran the risk of merging together. In any case, I imagine most deities would have a true self, or at least a lead aspect, that supervises the rest.

Then there are the various legends about a deity becoming split into enemy halves, or enemy deities who used to live as one, which usually come with a colorful description of the split. For examples:

Ahriman & Jazirian. The Twin Serpents of Law used to form a double ouroboros, each one holding the other's tail in their mouth. When they fought, it turned into a mutual bite. The separation was bloody, and neither has fully recovered yet.
Bahamut & Tiamat. Wielding a rough-hewn axe of adamantine, Erek-Hus cleaved Io from head to tail, only to see the two halves of his enemy reform as the metallic Bahamut and the chromatic Tiamat.
Beshaba & Tymora. When Tyche was poisoned by Moander and then healed by Selûne, it resulted in a weaker but healthy version of the goddess, Tymora, while the corruption gained a form of its own, Beshaba.
Selûne & Shar. In the beginning of Realmspace, the goddess of light, Selûne, and the goddess of darkness, Shar, saw themselves as one being, the Two-Faced Goddess. But when their daughter Chauntea demanded more warmth to nurture life, they became of two minds over the matter of giving Realmspace a sun.

These could all reflect a common mechanic wherein different aspects of a deity no longer tolerate each other. It is even possible that Io or Tyche are still alive and kicking somewhere on the Outer Planes, having simply lost several crystal spheres to their bickering aspects. Or, for a wilder and sillier theory, Lord Ao, creator and overgod of Realmspace, might be the Two-Faced Goddess wearing a fake beard.

The process could also be recursive. Io has a sibling called Chronepsis, and the two are sometimes represented as a dragon with nine heads consuming its own nine tails. In turn, Ahriman, Chronepsis, Io, Jazirian, and a multitude of other deities, are regarded by some as aspects of the World Serpent.


So planar travel from the Prime always happens from within one of the spheres, each of which is its own self-contained setting that gets to do whatever it wants. It's possible to travel between another plane and multiple spheres, but one will tend to wind up in different places in that other plane.On that note, I could see the World Tree cosmology coexisting with the Great Wheel.

The World Tree itself is a transitive plane of sort, which relies Realmspace to a few celestial dominions. These include Dweomerheart, home to deities such as Mystra and Azuth, and Brightwater, home to deities such as Sune and Tymora.

The evil counterpart of the World Tree is the River of Blood. That one relies Realmspace to fiendish dominions, such as the Barrens of Doom and Despair where dwell Bane, Loviatar and others.

But none of that stops Dweomerheart from being part of Elysium, or Brightwater of Arborea, as they are located in the Great Wheel cosmology. Similarly, the River of Blood could be a stream of the larger River Styx, with the Barrens being part of either Acheron, Baator or Gehenna.


For starters, locations in some planes — the Feywild, the Shadowfell, the Ethereal — directly correspond to locations in the Prime Material, and the easiest method of travel to such a plane generally leaves the traveler in the "same place" in the three conventional spacial dimensions. And it seems clear to me that there pretty much has to be something similar going on with the other planes too.A headcanon of mine is that the regions of the Elemental Planes that are uninhabitable expanses of a single pure element, these occupy the same coordinates as the phlogiston in the Material Plane. Similarly, the Feywild's deep space is the Positive Plane, while the Shadowfell's is the Negative Plane.


After all, if Sigil only has a finite number of portals, they only go to a finite number of places on the Prime, which all exist within some finite region of space.Or, at least, a finite number of active portals. And one day, Her Serenity might decide that Sigil has seen enough visitors from Oerth and Toril, and that it is time for some Ravnica and Theros instead.

[Naanomi]

Ahriman & Jazirian.[/B] The Twin Serpents of Law used to form a double ouroboros, each one holding the other's tail in their mouth. When they fought, it turned into a mutual bite. The separation was bloody, and neither has fully recovered yet.
Note: This happened *way* before they were Gods (or before there were Gods at all in a way we would recognize them by modern cosmological standards)... though Jazirian has since become a God (a lateral move, really, he is/was already more cosmologically important than any being that is 'just' a God)


WOn that note, I could see the World Tree cosmology coexisting with the Great Wheel.
We have other examples of 'semi-transitive' places out there... the infinite staircase, the mirror realm, perhaps the World Serpent Inn (or perhaps not)


Or, at least, a finite number of active portals. And one day, Her Serenity might decide that Sigil has seen enough visitors from Oerth and Toril, and that it is time for some Ravnica and Theros instead.
There is also the old Planescape principle of 'like attracts like', or as a part of 'center of all'... that you are just more likely by the laws of the Planes to run into things you are familiar with or expecting. If you are from Norseworld where the Norse pantheon reigns, you are more likely to run into Loki's divine realm while wandering around Pandemonium instead of Cyrics... likewise, you are more likely to find a portal to a familiar world on Sigil instead of a random other spot in the multiverse. The Great Wheel (especially, but not exclusively, the Outer Planes) are built on belief, perception, and expectations... in ways that can fundamentally effect the experience of the individual

[Devils_Advocate]

I remember 4e stating somewhere that different aspects of the same deity felt really uncomfortable around each other. It probably had something to do with an identity crisis, or perhaps they ran the risk of merging together.
Interesting. I'll admit that I was only speculating, so I don't actually have an informed opinion what's most common.


Then there are the various legends about a deity becoming split into enemy halves, or enemy deities who used to live as one, which usually come with a colorful description of the split.
I think that those are more the exception than the norm, given attention because the dualism involved is so notable, whereas relatively minor differences are hardly worth making a big deal about. Then again, I suppose that aspects can only be distinct from each other to the extent that the contrasts between them are significant. Not all contrasts are cause for conflict, but the clearest splits are most likely to be the result of irreconcilable differences.

I think that Angharradh has positive relationships with and/or between her aspects, but it's not clear to me that she isn't a union of three pre-existing goddesses, rather than them being derived from her. If she is the product of cooperation, one would of course expect her aspects to be allies. That seems like an unconventional arrangement, though.


The process could also be recursive. Io has a sibling called Chronepsis, and the two are sometimes represented as a dragon with nine heads consuming its own nine tails. In turn, Ahriman, Chronepsis, Io, Jazirian, and a multitude of other deities, are regarded by some as aspects of the World Serpent.
I see no reason why aspects of deities couldn't have aspects of their own. Perhaps all of the Powers are simply Nth-level aspects of the same entity. I'm sure that many of the Athar are fond of that theory.


A headcanon of mine is that the regions of the Elemental Planes that are uninhabitable expanses of a single pure element, these occupy the same coordinates as the phlogiston in the Material Plane. Similarly, the Feywild's deep space is the Positive Plane, while the Shadowfell's is the Negative Plane.
That makes sense, although I'm not sure how this newfangled Elemental Chaos fits into it, if at all.


Or, at least, a finite number of active portals.
Yeah, it's a bit more complicated than I acknowledged. Every portal in Sigil, if I recall correctly, requires a portal key. The portal key is what makes the portal a gateway to another plane. A single doorway theoretically could be a portal to an infinite number of places, with a different key for each location. But even so, the number of places that have already in practice been traveled to from Sigil, and/or that Sigil has been traveled to from, would still be finite. Unless Sigil has existed for an infinitely long time...


We have other examples of 'semi-transitive' places out there... the infinite staircase, the mirror realm, perhaps the World Serpent Inn (or perhaps not)
Oh, there are plenty of planar pathways (https://mimir.net/pathways/index.shtml) like Yggdrasil and Mount Olympus, and they don't all go through planes in the same order. The well-known and extensive River Styx and River Oceanus lend themselves well to the Great Wheel model, but what that model really has going for it is putting similar planes near each other. You can just lay out a graph of maximum Law to maximum Chaos from left to right and maximum Good to maximum Evil from top to bottom, and then place each Outer Plane in the appropriate spot, and the result is the Great Wheel model of the Outer Planes. But that doesn't mean that they're actually arranged that way in space. Showing them arranged that way in spatial dimensions is just an analogy to show how they're arranged in the relevant non-spatial dimensions, as is usual with graphs. Similarly, Planescape's Inner Planes can be described using 3 axes of Earth/Air, Fire/Water, and Positive/Negative, with the planes being arranged like the surface of a sphere.

But such arrangements depend on the qualities under consideration. There are innumerable ways to rank planes relative to each other. For example, Ysgard and Acheron, directly opposite each other on the Great Wheel, both have an "eternal battle" thing going on. If you were to order the planes from maximum amount of fighting to minimum amount of fighting, they might well be right next to each other! It doesn't make sense to call one model more correct than another without qualification, because statements about the arrangement of planes are only correct or incorrect with respect to some model. But when you want to do something, one model can be more or less useful than another for that purpose, which is what's worth worrying about.


There is also the old Planescape principle of 'like attracts like', or as a part of 'center of all'... that you are just more likely by the laws of the Planes to run into things you are familiar with or expecting. If you are from Norseworld where the Norse pantheon reigns, you are more likely to run into Loki's divine realm while wandering around Pandemonium instead of Cyrics... likewise, you are more likely to find a portal to a familiar world on Sigil instead of a random other spot in the multiverse.
Ah, so being related to each other results in things being closer together, as well as vice versa. There's some sort of connection to be made between the Unity of Rings and positive feedback loops, I think. Meeting acquaintances when you fire up the old infinite improbability drive must be frustrating if you want to get away from people you know, though.


The Great Wheel (especially, but not exclusively, the Outer Planes) are built on belief, perception, and expectations... in ways that can fundamentally effect the experience of the individual
It's weird that the Power of Belief works outside of the reach of the Outer Planes. Isn't the explanation that the Outer Planes are made out of belief? I'd have thought that the Inner Planes, lacking direct connection to the Outer and being planes of Substance would be at least pretty insulated from such effects. And I'm not alone; there's a reason that a lot of planars posit that there must be some sort of Ordial Plane connecting the Inner Planes to the Outer Planes, total lack of direct evidence of its existence notwithstanding. (And, hey, if enough people believe in it...)

[Naanomi]

It's weird that the Power of Belief works outside of the reach of the Outer Planes. Isn't the explanation that the Outer Planes are made out of belief? I'd have thought that the Inner Planes, lacking direct connection to the Outer and being planes of Substance would be at least pretty insulated from such effects. And I'm not alone; there's a reason that a lot of planars posit that there must be some sort of Ordial Plane connecting the Inner Planes to the Outer Planes, total lack of direct evidence of its existence notwithstanding. (And, hey, if enough people believe in it...)
That isn't quite right... the power of belief, even of many beings, doesn't shape reality that way (except of course in the way it does the Outer Planes, Astral, and a few other places... but even there fundamental things exist beyond that); this isn't a 'M:tA' style Consensual Reality... but rather that every being's *experience* of reality is focused upon them and their own perspective. All beings are the center of their own universe. And yes, that does include the Inner Planes which... while not fundamentally twistable by thoughts and feelings and faith like the Outer Planes... still get experienced by living beings from that central perspective which is at least part of why people can reliably find the City of Brass in an infinite Plane and the like (but also why there are not infinite visitors there at any point in time).

It... doesn't make perfect sense, but Outsiders would tell us that is just because us Prime types are not built to understand what is pretty obviously true

[Devils_Advocate]

We obviously each have our own unique perspective, but not as much follows from that as the Signers are inclined to argue. Why would that mean that we tend to encounter the familiar no matter where we go? Perhaps it's simply that we only tend to recognize and respond to the familiar, whilst the significance of other things eludes us. A confirmation bias sort of thing.

The Outsider creature type introduced in 3E isn't a thing anymore in 5th Edition. And so far as Planescape is concerned, Outsiders are the usually-clueless Primes who sometimes show up in Sigil. Apart from their ignorance, they're notable for their lack of allegiance to planar organizations like the Factions. Consequently useful for dealing with business that folks want meddlesome groups to stay out of, they're often hired for mercenary work and the like. And if one goes missing, likely no one will even notice...

[Unoriginal]

The 5e books do not mention or imply that belief shapes any of the Planes by itself. The belief = power is pretty much only a thing for actual deities now.


There is a relationship between the mental/moral makeup of mortals and the nature of the Outer Planes still, though.

[Millstone85]

Note: This happened *way* before they were Gods (or before there were Gods at all in a way we would recognize them by modern cosmological standards)... though Jazirian has since become a God (a lateral move, really, he is/was already more cosmologically important than any being that is 'just' a God)I would phrase it as them having "primordial divinity" before they had "faith-based divinity", if that makes sense.

Though the MM claims that "Couatls were created as guardians and caretakers by a benevolent god not worshiped since the dawn of time, and which is forgotten now by all but the couatls themselves", which would make Jazirian kaput as a faith-based deity.

I wonder then if she is now a petrified corpse drifting through the Astral, or if her primordial divinity proved stronger than faith deprivation.

Or she may be slumbering in the manner of Merrshaulk and other serpent gods. It is my headcanon that feathered yuan-ti are a thing even outside of Eberron.


It's weird that the Power of Belief works outside of the reach of the Outer Planes. Isn't the explanation that the Outer Planes are made out of belief? I'd have thought that the Inner Planes, lacking direct connection to the Outer and being planes of Substance would be at least pretty insulated from such effects. And I'm not alone; there's a reason that a lot of planars posit that there must be some sort of Ordial Plane connecting the Inner Planes to the Outer Planes, total lack of direct evidence of its existence notwithstanding. (And, hey, if enough people believe in it...)According to the DMG, "If the Inner Planes are the raw matter and energy that makes up the multiverse, the Outer Planes provide the direction, thought, and purpose for its construction". I don't know if that was always the case, or if that's a leftover from 4e (where the astral-vs-elemental conflict was pretty much Law-vs-Chaos). Anyhow, it implies some level of interaction between the Outer and Inner Planes.

Here is another headcanon of mine: 5e Primus went through a more succesful version of his 4e backstory. In that edition, Primus used to be a being of the Elemental Chaos who, channeling the power of what he then called the Accordant Expanse, tried to coalesce four distinct Elemental Planes. An entity of the Far Realm ruined that plan, after what Primus left the Elemental Chaos for the Accordant Expanse. He left in pieces, actually, his body now a collection of modrons. Anyhow, that's when the Accordant Expanse became the Clockwork Nirvana.

I know it doesn't match well with the War of Law and Chaos of old Planescape.