The Transitive Planes are those that exist between the outer and inner planes, acting as the sea upon which those planes float. They are very different, with the Ethereal Plane between the inner planes being a misty place where matter is created by pure will alone, and the Astral Sea between the outer planes being a place of great expanse where all things eventually end up. They do, however, have one thing in common: Dreams. The dreams of mortals and immortals alike begin on the Ethereal Plane, where they take form and coalesce until the dreamer wakes, at which point the dream makes its way to the Astral Sea. In both cases, the dreams seem and feel as real as any plane, which had led many to wonder whether or not the inner and outer planes themselves are little more than the dream of some great being, whether or not they will one day awaken, and what would happen if they ever did.

Ethereal Plane

Travelling the Ethereal Plane:

In the Great Wheel cosmology model, the Ethereal plane exists adjacent to the Prime Material Plane and connects it to the Inner planes (the Elemental planes plus the Energy planes). The Ethereal touches the Prime at all points through what is called the Border Ethereal (aka. The Ether Shore. The non-Border region is called the Deep Ethereal. While in the Border Ethereal, a traveler can still see into the adjacent plane but only dimly and not very far, whereas those on the bordering plane cannot see the traveler without magical detection. Verbal communication is not possible between the Border Ethereal and the bordered plane. The Ethereal is unique among the many planes in that an individual can exist in two planes simultaneously: the Border Ethereal and the adjacent plane.

When a traveler crosses into the Border Ethereal, she and all her possessions are converted to their Ethereal equivalents, metal becomes ethereal metal, flesh becomes ethereal flesh and so on, allowing free movement (in most cases) in any direction through the solid matter of the adjacent plane. Since everything was permeated with ethereality, an air-breathing creature can breathe ethereal air and cannot drown in an ethereal lake nor be crushed by an ethereal rock. However, not all in the adjacent plane was insubstantial. Living things larger than one-celled animals generate an aura that radiates around them and prevents passage to their interior, so an ethereal traveler could not place a weapon inside a living creature where it would materialize and cause damage. A jungle would be an extremely tortuous maze to navigate; it would be much easier to float above the vegetation or pass below its roots. Dense metals such as lead or gold can also prevent the passage of ethereal matter. And finally, some magic spells and alchemical mixtures can form an effective barrier.

Travel in the Ethereal and Border Ethereal is accomplished by force of will—you wish to go somewhere and you do, at your normal rate of movement. There is a sense of up and down but no real gravity exists. Objects released from possession will hover where they are dropped; it is impossible to fall in the Ethereal plane. However, because everything is accomplished by will, it is possible that other creatures with greater will can create circumstances that cause actual damage, influence gravity, create realistic dangers, or even directly manipulate other travellers.

There are also placed where the Ethereal Plane borders other planes, and one can pass between them. To get to another plane, one has to pass through a curtain of vaporous color into the Deep Ethereal, then traverse that region until reaching the curtain that demarcated the Border Ethereal of the destination plane. Each Inner plane and demiplane has a curtain with a unique color. The Prime Material plane’s curtain is turquoise. If the (usually magical) ethereal effect wore off while a traveler was in the Deep Ethereal, he would immediately be forced through a random curtain at a random location in the Border Ethereal and deposited on the plane which it bordered.

When you pass through a curtain into the Deep Ethereal, time slows down to one tenth the rate it flowed in the Border Ethereal and the plane that it bordered. For every ten hours spent in the Deep Ethereal only one hour passed on the other side of the curtain. Metabolic and other natural processes slow down also, so it does not feel like ten hours, when you cross back through a curtain into a Border Ethereal you are only an hour older and an hour hungrier.

The Deep Ethereal swirls with large blobs of proto-matter (imagine a cosmic lava lamp) which could form a demiplane when a critical size was reached. Powerful wizards, technologists, or demigods could also bend the proto-matter to their will and create a demiplane. These nascent planes might exhibit some of the characteristics of the Inner planes or the Prime, but with their own rules of gravity, material make-up, etc., and even support life. Most demiplanes eventually collapse into themselves and break up or merge with another Inner or Prime Material plane. This is done temporarily by nearly all living creatures in the form of dreams.

The Will is the Way:

The Ethereal Plane is the glue that binds the inner planes. It is a place of little substance, but with proto-matter in abundance that can be manipulated by sheer will. Travel, likewise, occurs by sheer will. Therefore, it stands to reason that if the will of two creatures conflict, the one with the stronger will would succeed in manipulating this matter. These are done by contested Perception (Wisdom) checks. Creatures that have a common will can assist this check with the Help action, granting advantage to the roll for that creature. If a third creature joins, they can also use the Help action further to impose disadvantage on the roll for the opposing creature.

Veil of Sleep:

Many folks believe that dreams take place in the Astral Plane, but that is not where they originate. It is true that they eventually make their way there, but they begin at proto-matter in the ethereal. Once done they do not disappear, but journey to the Astral where they take the form of clouds drifting in the endless sea.

Dreams take form on the ethereal plane. It’s possible for travellers to enter and even take control of dreams. When a dream is created, it is the dreamer forming proto-matter in a little pocket of the plane. From the outside, a dream appears similar to the world of the border plane, but with a shimmering, distinctive border known as the Veil of Sleep.

The dream need not be near the sleeper and can appear nearly anywhere on the plane. The dream and dreamer take whatever form they wish in their dreams. It is also possible to wrest control of a dream from a dreamer by force of will. However, when the dreamer loses such control, it becomes a nightmare, and can be unpredictable for those not used to handling such things.

Most creatures do not consciously control their dreams. A few, known as lucid dreamers can. However, just because control is subconscious doesn’t mean that the dreamer isn’t aware if someone else has any control. The dreamer can always tell instinctively when things in the dream “aren’t right.” Dreams without full control of the dreamer are experienced as nightmares. In a dreamscape, all sentient creatures, even visitors take on their idealized dream form. The one dreaming a dream is known as the principle.

Ruptures:

Some creatures feed off the psychic energy of dreams. Some merely enjoy viewing or controlling the highly personal dreamscapes of sentient beings. Creatures that would interfere with dreams, or lucid dreamers themselves, must be careful to not push the limits of the psyche creating the dream too far. Those that do risk a Dreamscape Rupture.

Normally when a dream ends the proto-matter returns to the ether and the dream moves on to the Astral Sea. When a rupture occurs, the proto-matter does not immediately return to the ether. Instead, elements of the dreamscape leak out of the veil of sleep and roams the ethereal plane. The elements slowly decay back to the ether over 1d100 hours, but until then travellers too close to a rupture might find themselves in lava, stalked by vampires, or some other terrible nightmare scenario.

Creatures of profound will can create and maintain ruptures, effectively converting part of the border ethereal into a realm of their own making. Most of these float throughout the ethereal and are called dreambergs. Others reside directly on top of the ethereal shore, practically touching the prime plane. A small exception of them actually influence the real world.

Places of Interest:

The Castle at the Edge of Time – The home to the last member of the Olefin Temporal Society. Long ago, a wizard (Aionias) and his apprentice (Montgomery) placed themselves into magical statis. They had been experimenting with planar travel for some time and decided to take an extended break from reality to study the ethereal plane. They’ve become proficient enough to have the will to create and maintain a castle to act as their home. They physical forms reside in a storage closet in the basement of the Ars Arcanum in Ashtesma.
The Body Luminous – Home of the Ghostwatch (Kyr Shar in elvish), a group of elves tasked by Angharradh the elvish goddess of the moon to watch over the dreams of elves and protect them while they sleep. Elves do not sleep as humans do. They can dream, however, if they enter a prolonged trance or utilize magical or chemical assistance. Their dreams tend to be more literal and grounded in reality, which makes them more susceptible to influence by those that would cause nightmares simply because they are less equipped to resist the uncertainty of losing control of their dreams. The Kyr Shar, known as ghost elves, ride the ethereal plane on Ostrich made of ether which obviously provides them no real benefit given the physical nature of the plane, but allows their literal elven minds to more easily focus their will on faster movement. The rupture itself upon which Ghostwatch is build is the principle of a Baelnorn – an elvish lich – and priestess of Angharradh, who was placed into magical stasis and now resides somewhere on Arborea in the goddess’ domain..
The Embryonite – Possibly a pure myth, but some say in the ether is a planet sized wasp, which nourishes and fosters a demiplane in its thorax.Potentially the rupture of a strange and powerful creature.
Farer’s Freehold – Oddly enough – there resides a city in the ether floating somewhere in the deep, or so the stories say. It is the home of Rilmani – humanoids that make their home here. Unlike other ruptures, it has no principles. The Rilmani have simply lives here long enough they can manipulate proto-matter on their own.
Leiscter’s Gap – A portal created by a wizard named Leiscter that is one of the few permanent portals. The other side leads to Leister’s former workshop, dark and long unused which was sealed from the outside to prevent anything coming through the portal. The workshop is underground, beneath an abandoned Ottimizzarian Order outpost in northern Fragrantia.From the ethereal plane side, the gap appears to be a chunk of spherical rock with iron rods sticking out of it like antennae, which has a chain coming off it. The chain connects to a portal of light. Both the rock and chain seem unaffected by the strong currents so close to the Gap.
Ommiad’s Web & Ommiad’s Knot – The rupture of a high-level priestess of Llolth, who sleeps eternally after being cursed by her goddess for failing to fulfill her wishes on the prime plane. Rather than turn her into a drider, Llolth used her to create this rupture, giving her a foothold into the ethereal plane. The rupture is essentially a giant spider web. In the center of the web is a tangle of spidersilk bundles, known as the Knot. Lloth has been known to use phase spiders to wander the ether and capture prey to bring back to the web, where they are devoured by the spiders, or plane shifted to the goddess’ temples in the Underdark to act as favors to her faithful in the form of slaves or sacrifices.
The Poisoned Tree – Domain of Granny Titchwillow.

The Black Abyss:

The Deep Ethereal is rumored to contain a center, and in that center is The Black Abyss, said to be the anchor that holds the inner planes in place. It is best described as the demiplane of entropy – a plane is a state of permanent dissolution.

Ethersickness:

Travellers to the plane are sometimes severely affected by it. When a new traveller first visits the plane, or if more than a year has passed since a traveller was last in the Ethereal Plane, they must make a DC 15 Constitution check. If they fail, they become disoriented by the lack of horizon, the swirling mists and currents of the plane, and the lack of true gravity. Those that succeed manage to retain their “inner” orientation, and remain unfazed.

Those suffering from ethersickness suffer disadvantage on all ability checks while on the Ethereal Plane, and disadvantage on Wisdom saving throws to overpower the will of other travellers not suffering from ethersickness. The only cure for ethersickness is to leave the place for at least an hour. The save is repeated should they re-enter the plane after waiting.

Cerebral Parasites:

These tiny beetle-like creatures are entirely invisible from the prime material plane, though their presence can often be felt when a place is infested with them. Once on the ethereal plane, they become visible and the extent of the infestation becomes apparent. Their purpose is to feed off of psychic energies, and their ability to feed on both dreams and living creatures across the ethereal shore means they can have a significant impact on their hosts. Dreams will become nightmares of bug crawling all over skin. Living creatures will feel creepy-crawling on their skin and an unsettling paranoia sets in. For travellers on the border, these parasites have an even more profound effect. For every hour spend in the presence of an infestation they will gain one level of exhaustion.

Hauntings and Ghosts:

When a soul refuses or cannot return to an outer plane upon death, the spirit becomes trapped in this plane between planes. Ghosts reside on this plane, and they are drawn to the living that enter their realm. See below for a chart of potential hauntings, but if they are in an area with known ghosts, this is where they’d come in to play.

When a ghost uses its possession ability on a traveller, the traveller itself is not possessed, but their physical body is. The traveller will see the ghost enter them, and then through the border ethereal they will see the spirit walking off with their body. A traveller that does not stand ready to retake their physical form when the spirit is expelled is unlikely to ever find it again. If not, then they also join the chorus of dread spirits haunting the ethereal plane.

Creatures that Can See into the Ether:

Creatures with gaze attacks like cockatrice, basilisk, and medusa can see into the ether and turn them to stone through the border. The ethereal plane near their lairs is full of stone travellers who do not appear on the prime plane – only the creature themself can see the entirety of their collection.

Other creatures can see into the ethereal plane as well. Kuo-Toa, mordenkainen’s faithful hound are two examples. Being able to see into the ethereal plane does not necessarily mean a creature can enter or affect anything on it.

Ether Marauders:

The Shadowfell also borders the Ethereal Plane. It’s not uncommon for a mysterious group known as Marauders to ride out over the vast plane along the border of the Shadowfell and snag spirits and travellers that wander too close.

Ether Cyclones:

An ether cyclone is a serpentine column that spins through the plane. The cyclone appears abruptly, distorting and uprooting ethereal forms in its path and carrying the debris for leagues. Travelers with a passive Wisdom (Perception) score of 15 or more receive 1d4 rounds of warning: a deep hum in the ethereal matter. Travelers who can’t reach a curtain or portal leading elsewhere suffer the cyclone’s effect. Roll a d20 and consult the Ether Cyclone table to determine the effect on all creatures in the vicinity.

Cyclone Effects

d20	Effect
1-12	Extended journey
13-19	Blown to the border ethereal of a random plane (roll on ethereal curtains table)
20	Hurled into the Astral Plane

Ungoverned Portals (Ether Gaps):

Like other planes, occasionally an ungoverned portal will open to the ethereal plane. When this happens, the currents of the plane seek to suck toward the opening like water down a drain. Creatures familiar with the ethereal plane, such as ghosts, can sense this change of current and are drawn to these portals a potential escape. Like water in a drain, the current also gets stronger the closer you are to the terminus. Creatures within 60’ of the portal must do a Will check or begin being pulled into the portal. The portal could empty out into any of the inner planes – use the Ethereal Curtains table to determine which one.

The most common effect of an ether cyclone is to extend the duration of a journey. Each character in a group traveling together must make a DC 15 Charisma saving throw. If at least half the group succeeds, travel is delayed by 1d10 hours. Otherwise, the journey’s travel time is doubled. Less often, a group is blown into the Border Ethereal of a random plane. Rarely, the cyclone rears a hole in the fabric of the plane and hurls the party into the Astral Plane.

Ethereal Curtains

d8	Plane
1	Material Plane
2	Shadowfell
3	Feywild
4	Plane of Air
5	Plane of Earth
6	Plane of Fire
7	Plane of Water
8	Elemental Chaos

Rilmani:

Rilmani are not natives to the ethereal plane, but they have been here for centuries and have quickly adapted to like here. They are colorless humanoids. Their skin is grey, their clothing of proto-matter is grey. From a distance they and their city blend in completely with the surrounding mists. They congregate in a single city called Farer’s Freehold, but venture out into the ethereal sea to, as they put it, ensure the ethereal plane remains balanced. They are humorless. The concept of jokes is entirely foreign to them. They are always serious and very literal. They have good relations with the ghost elves, as they have similar missions.

They are willing to do business with travellers, harboring no ill will to those who merely pass through the plane. They do, however, take exception to those that would stake a claim with aims to take over the plane. Since the ethereal plane spans all inner planes it’s not unheard of for an ambitious genie, wizard, or hag to try to take over the plane itself.

They do have items available in their city, but they will be made of proto-matter which doesn’t phase back to the material plane. The food they have will nourish traveller’s though, as the traveller is temporarily in an ethereal state.

Astral Plane

The Astral Plane is the realm of thought and dream, where visitors travel as disembodied souls to reach the planes of the divine and demonic. It is a great, silvery sea, the same above and below, with swirling wisps of white and gray streaking among motes of light resembling distant stars. Erratic whirlpools of color flicker in midair like spinning coins. Occasional bits of solid matter can be found here, but most of the Astral Plane is an endless, open domain.

Dream begin on the Ethereal plane, but where do they go once the dreamer wakes? They don’t disappear. Words, once spoke, cannot be unspoke – where do those go? The answer is the astral sea. Eventually, all things paradoxically begin and end in the Astral Plane. All gods and planes are born from it and, the legends say, all return to it as well.

The Astral Plane is one of the Planes of the Great Wheel cosmology… Wait, that’s not entirely correct. In the most technical sense, it’s not even actually a “plane” in the sense of a bound dimensional space like the others.

The Place That Isn’t

The whole place is essentially the empty place between everything. It’s not a place the way you can actually think of it; it’s actually the absence of normal space and time, being a realm of pure concept. It’s a realm between concepts. If you think of all the Outer Planes representing certain cosmological ideals and metaphors and such, the Astral Plane is simply an area where concepts haven’t taken a form yet. It is the infinitely small space between everything, which makes it infinitely big as well once you get there.

Confused? Good. Now you get the point. These attributes give the Astral some pretty unique and fun traits.

No space means there is no gravity, and no real sense of direction relative to anything. There are things that drift there in the vast emptiness, but due to the very subjective nature of distance and direction, finding such things on repeat visits can either be simple or hard. So how do you move? Pure thought, berk. Anything with an Intelligence score can fly as fast as their thoughts can take them (basically perfect fly speed of Int score x 10). Objects and brain-dead creatures can’t move, but can be pushed.

No time, so nothing ages due to metabolism not occurring. For some things, this is great: you can’t suffer continual damage from things like poison or disease, you can’t go hungry or thirsty, and you don’t age. The problem is, you also can’t naturally heal; only magic will do the trick. Now, here’s the catch: all of your missed time catches up instantly when you leave the Astral to a normal time area. So, if you had a disease while in the Astral for 20 years, you just suffered 20 years of its progress at once. Same with aging. The trick is, you want to cure stuff with magic before leaving. There’s a line that you’ll be hungry and thirsty, too, but won’t die from it as long as you start gorging yourself on meatbread or something.

These things basically make the Astral Plane the biggest wizard playground in the multiverse. Some of them just retire there to the Astral and use magic to pop in from time to time on other planes.

The Astral Plane is, for the most part, a dreary and empty expanse of nothingness, broken up upon by sporadic landmasses, the petrified corpses of dead gods, the gargantuan worm-like “astral vortexes”, and color-based portals to various planes. There are a handful of sapient races indigenous to the Astral Plane, but the most well-known are a bunch of immigrants, the Githyanki. Living creatures don’t age here, so the githyanki need colonies in the prime material plane for their eggs to hatch and their children to grow up. They also build ships and cities out here, the biggest on the corpse of a dead god that their leader is trying to eat.

Lots of people who go here prefer to travel via astral projection, leaving their physical body behind and letting an astral body glide through the plane. This is generally fairly safe, but they need to keep track of their “astral cord”, connecting their astral and physical bodies, which manifests as a very tiny silvery string. If this gets severed (which not many things can, but it is the intended purpose of those githyanki silver swords), you’re toast. If it’s not, you can tug on it to get back fairly easily.

Things To Do

As noted, the githyanki live in this strange place, doing raids and other mean shit. But they do have a need for trade and commerce, specifically in armaments and other military goods, and they’re too stuck up to dirty their hands with digging up iron or manufacturing anything if they can help it.

One of the most prolific reasons to be here, though, is creating a demiplane through various magic spells or psionic powers. Even as the most frugal interpretation of the rules, having your own private demiplane is simply great. Aside from creating truly anonymous planar prisons for hated enemies, you can naturally build your own stronghold in such a place, or use it as an agricultural business or factory site to assemble items, or whatever.

Another great thing, because the Astral touches everything, you can spend time searching for links to other planes, anywhere.

Constelations