Ethereal Plane

The Ethereal Plane, also described as the Waveless Sea, is a mist-filled, colorful dimension that exists alongside the Prime Material Plane and the Inner Planes, the elemental planes that make up The Material Plane like the Plane of Fire or Plane of Water. It acts as an adjacent world where it touches every part of the Material and Inner Planes, and contains a dense fog of what many referred to as “Planar Soup”.
There are two major sections of the Ethereal Plane known as the Border Ethereal and the Deep Ethereal. The Border Ethereal are the sections of this plane that are directly adjacent to a plane of existence, either a Material World, an Inner Plane or a demi-plane, and anyone on the Border can look into that adjacent plane as if they are looking through a frosted window. Peering through this foggy view allows a creature to see into the adjacent world, to see creatures moving, and the landscape around them. Unfortunately for those trying to spy and seek information, being on the Ethereal muddles small details like writing and only the loudest of screams can be faintly heard, muddled by the fog of the Ethereal.
The Deep Ethereal is a section of this plane that is not adjacent to any plane and is used to travel from one Border to the next. The Deep Ethereal is like floating through a vast ocean as the fog obscures your vision almost completely and there is no floor to situate yourself to but rather the endless fogs and colorful curtains that periodically appear as you travel through the plane.

Ecosystem

An Outsider’s Perspective
Most visitors to this plane are typically here for a specific purpose, either to seek information on their own world or to travel to another plane of existence. Those seeking information rarely leave the Border Ethereal, and those traveling from one plane to the next quickly move through the Deep Ethereal. Due to the limited visibility in both planes, there are hidden dangers that lurk in the multi-colored fog that unwary visitors might stumble into and never out.
The Border Ethereal is a foggy reflection of the adjacent plane you are viewing. If you venture into the Border from your Material World, you see a multi-colored fog-filled world as if seeing the world through frosted glass. You can journey forward and backward, to the side or anywhere you want, including moving up into the ‘sky’ and down into the ‘ground’. Drifting through objects is easy as walking and bypassing stone walls, earthen works and guards are trivial when you can simply guide through or around them.
The Deep Ethereal is a plane with no ground or sky, but rather roiling mists that fill and obscure all vision. A visitor drifts through this void, traveling forward with physical effort and mental determination. There are no structures or landmarks to guide a visitor on their path, instead, to continue their journey, they must hold the place they wish to go firmly in mind until they find the correct color curtain to take them to that plane’s Border.
A Native’s Perspective Very few creatures can claim that they are natives to this plane, though many have developed abilities to allow them to use the plane for their own purposes. Phase spiders are one of the most well-known creatures that use the Ethereal Plane, though they are normally only found in the Border Ethereal where they are close to their nests located on The Material Plane.
There are a variety of creatures who now claim this plane as their home, drifting from countless other worlds and adapting to survive here. Frequent travelers will construct supply drops where they leave rations and water behind in the Deep Ethereal, constructing makeshift ‘shelters’ from the planar stuff that populates this plane. Other creatures will scour the ethereal matter looking for travelers, adventurers, and anything else as it hunts for food and treasure.
The creatures that can truly claim they are the natives of the Ethereal Plane are just as strange as the plane itself. Creatures like the Meme, a creature that resembles a humanoid under a bedsheet of strange phantasmal material, or the Tween, shadow creatures that latch onto living creatures and acts as a sort of second shadow to them, are all the strange types you might find hunting and haunting throughout the Ethereal Plane. These creatures behave in strange ways, though they are mostly solitary which is good news for any traveler caught in an ambush by the natives.
Atmosphere The Ethereal Plane has no atmosphere beyond the mist that fills every part of this plane. This strange mist is thought to be the bleed-off residue of materials from the planes it connects and is called the mists of creation; many theorize that the mist is not a distinct element but rather the possibility of an element. This means, that all a creature must do is force the mist into an element, and it could transform into any element of that creature's choice, though no one has been able to do much with the material. Luckily, a creature can easily breathe in this atmosphere as if their mind and body are unconsciously able to transform the mist into whatever atmosphere they require to breathe. A few of the more dedicated travelers and explorers of the Ethereal can turn the possibilities of this mist into actual sustenance, allowing them to subsist solely off of the mist they breathe, though many claim that they still feel the pangs of hunger.

Tourism

Travel to the Plane Traveling to the Ethereal Plane can be difficult for anyone without magic or enough wealth to buy magical items. The most common way of arriving in the Ethereal Plane is by casting etherealness or using a gate or plane shift spell to arrive in the plane. Magic items that allow for temporary travel in the Ethereal Plane are objects like the Oil of Etherealness or the Armor of Etherealness, once the item wears out of its magic, the user is immediately returned to the world they originated on.
Some travelers have claimed to have found portals to the Ethereal Plane, and that instead of the color pools, like those found on the Astral Plane, they resemble glimmering curtains of light similar to the strange lights that appear in the far northern or southern skies known as auroras. Other creatures have developed their own methods of traveling to the Ethereal Plane, like the phase spiders' innate ability or the hag’s heartstone that allows them to move into the Ethereal.
Traversing the Plane Moving through the plane is much like physically walking on the adjacent plane, except you don’t have to worry about objects or walls getting in your way. Creatures can walk in any direction they wish, walking through the ground or over walls. While walking in the Border Ethereal, a creature sees a multi-colored fog that resembles their location in the adjacent plane and they can walk through and around any object they wish. If they were standing in The Material Plane in front of a castle, and then cast etherealness on themselves, they would be standing in that same spot but on the Ethereal Plane, they could then walk through the stone walls and up into the sky to spy on the Royal Family.
Though there are limitations to where you can go while in the Ethereal Plane, and many assassins have been disappointed when they simply couldn’t reappear in The Material Plane with a dagger re-materializing inside of their target. Every living creature gives off an aura into the Ethereal Plane that is impossible to pass through, extending about a foot from them. Dense metals, like gold or lead, also block passage through them, their composition too dense for a creature to flow through it. This allows people on their planes to protect important locations, like treasuries, from would-be thieves - though lining a substantial-sized room can be a very costly process.
To travel from the Border Ethereal to the Deep Ethereal, a creature must will themselves to the Deep Ethereal and find the color curtain that will transport them into the Deep. For travelers going through the Deep Ethereal, not only must they physically move through the mists, but they must also will themselves to their destination, picturing it in their mind. This is a long process that might require several days or hundreds of hours of walking to journey from a Border Ethereal bordering the Material World to a Border bordering the Plane of Fire. If a creature decides to walk through the Deep Ethereal without a clear picture in their head of the destination, they will never find a way out of the Deep Ethereal and live out the rest of their days in its roiling mists.
Protomatter The mists of the Ethereal are made up of existence itself, though it doesn’t take on a specific appearance but rather appears as a dense fog that is white and blue-tinged. This material is thought to be reality, the material that creates the planes and makes ideas and laws of the universe real. This material is more than just an abstraction, but reality as those with the mind to do so can shape and collect this matter in the Ethereal Plane. This material comes in three different forms: Ephemeral, Quintessential, and Stable.
While the material is Ephemeral, it is light and fluffy like a snowflake and is easy to walk through and not even notice on your journeys. This material flows through the Ethereal Plane as if stirred up by a wind and can be compacted into the next form. Quintessential feels like heavy, dense cork and is protomatter in a temporary state of physicalness. Quintessential can form quickly when too much Ephemeral matter sticks together or by a willful creature trying to produce a solid object out of matter, though this form is always temporary. Stable matter feels like metal sheathed in thin layers of leather and is stable for eons unless forced back into its previous states. While this Stable matter floats through the Ethereal Plane, it slowly gathers more and more matter, building larger and larger bergs of Stable matter.

Type

Plane of Existence

Location under

Inner Planes