The world is a strange place, and by extension, the universe is even stranger. Common knowledge of the planes may be found here.
The Mortal World
Also known as the material world, it is the home plane of the Coalition, as well as most of the Champions. The mortal world was created by the Primordials and perfected by the Gods, and hovers in the center of traditional depictions of the known universe, separating the Astral Sea from the Elemental Chaos. It is a finite world, where the elements are balanced in perfect harmony, upset only by rare natural catastrophes.
Many empires have spread across its surface in ages past, but now the kingdoms are in decline, and the most powerful nations are glorified city-states. Monsters rule the wilderness, preying on smaller settlements and travelers. Civilization in the mortal world is little more than points of light in an ocean of darkness.
Beings who hail from the mortal world have the Natural origin. They are often referred to as mortals, but the term can also be used to describe any non-immortal.
The Astral Sea
Here, the vast majority of the pantheon have founded their various dominions. Evil and Good deities alike share this place, although it helps that the Sea is a dimension of infinite space. Astral dominions vary in size, but may be as large or larger than the Mortal World itself. These locations are separated by incredible distances, but the plane is littered with portals called color veils that can teleport travelers to their destinations in an instant. The rest of the plane is empty space, a purple-tinted void that glitters with violet light and the twinkle of distant stars.
The Astral Sea is also home to the githyanki, and from here they make their deadly excursions into the mortal world using their extensive portal network.
Beings who hail from the Astral Sea have the Immortal origin. Githyanki have dwelt in the Sea for centuries, but this doesn’t change their Natural origin.
The Elemental Chaos
A roiling, violent plane, full of lakes of lava, endless storms, and floating earthbergs. The Chaos is an infinite expanse of raw elements in their purest form. Only the hardiest of creatures can survive long in this plane, although stable redoubts do exist where even frail mortals can reside.
The Elemental Chaos was once home to the Primordials, but those few who remain after their defeat in the Dawn War are either powerless or imprisoned. Their servant races, the archons, still wander it, often selling their services to more powerful individuals, like efreeti. The genasi also live here in scattered settlements, others have moved on to the mortal world to more fully embrace their separation from the Primordials.
The githzerai have built many monasteries here, seeking to find inner order in the midst of outer chaos.
Beings who hail from the Elemental Chaos have the Elemental origin. The githzerai, however, are Natural creatures.
At the bottom of the Elemental Chaos is a pit. Into this pit has been poured infinite hatred, violence, and evil. This corruption of the plane’s energy is known as the Abyss, and from it spawns all manner of demons. Reason dictates that since it has a beginning (and presumably an end), it cannot be infinite, but no two sages agree on the number of layers the Abyss comprises. Too few who venture there ever return to add to the mortal world’s collected knowledge.
Demons are destructive, lawless creatures bent on the eradication of all life. They wage endless wars against angels, devils, and their neighboring elementals. They serve no god, and were never in league with the Primordials either – they’re on a side all their own. They are led by powerful Demon Lords, the most prominent of which is Orcus, Prince of Undeath. No other creatures reside in the Abyss with the demons, unless you count their numerous captives, tortured and experimented on using unspeakable forms of magic.
The Abyss is a part of the Elemental Chaos, so all demons have the Elemental origin.
Where shadows cover the land and the fallen roam, that is the Shadowfell. It is a dark realm filled with palpable despair, and the energy that courses through it nourishes the undead as it sickens the living. Ghosts, ghouls, zombies, vampires and more call this plane their home, and they are granted strange powers while blessed by its darkness.
The shadar-kai also make their homes here, blessed by the Raven Queen to embrace this dim realm. They used to resemble humans, but their sullen eyes and pale skin now mark them as things of shadow.
The Raven Queen herself holds court here in Letherna, rather than from a dominion in the Astral Sea. From her ebony throne, she holds the souls of mortals in judgment. It takes about a month from the time that a freshly dead individual arrives until its appointment with the Dark Lady; after that month, resurrection becomes impossible, as the person will have passed on to their final fate. Those who serve the Gods have may be granted life after life as exalted, while the selfish and evil become damned and are imprisoned in Hell. The vast majority of souls, however, pass into the Hereafter. Only the Raven Queen knows what awaits there.
Beings who hail from the Shadowfell have the Shadow origin, including shadar-kai. The Raven Queen and her angelic servants, however, are Immortals.
A verdant paradise, much of the Feywild resembles the mortal world, but at the pinnacle of its natural beauty. The plane’s topography is very similar to the world’s, and it is said that the two reflect each other on some level. In fact, on certain days, regions of the Feywild shift into the natural world, allowing travel between the two planes without the use of a portal.
Eladrin have built many shining cities in the sunny places of the Feywild, but the plane has its darker features as well. Creatures both mischievous and ferocious inhabit the wilderness, and it can be very dangerous for outsiders.
Archfey rule over the many regions, and their powers can change the land around them, as well as their subjects. Treants who dwell in the land of the Winter Court, for example, may shed their leaves and gain a resilience against the cold. Archfey are neither good nor evil, but their great power makes them regard mortal races as inferiors. A single archfey may welcome powerful mortal heroes one day and take slaves from the natural world on the next; all the archfey respect is power.
Beings who hail from the Feywild have the Fey origin. This includes many races that migrated to the mortal world long ago, including elves and gnomes.
The Far Realm
Little is known of the Far Realm, as portals that lead to it are prohibitively rare, and more mundane forms of transportation would take impossibly long to reach it (hence its name). Only the most insane of mages dare to summon creatures from this place, as these beings are beyond the power of most to control.
If demons are evil given form, then the beings of the Far Realm are madness given form. Hideous fleshy piles adorned with far too many eyes and mouths, tentacled beasts, and other inhuman horrors populate the Far Realm, not to mention the sinister brain-devouring illithid, known to many as mind flayers.
Beings who hail from the Far Realm have the aberrant origin.
Scattered around the universe are small pocket dimensions – planes of incredibly limited size. The smallest of these are the collections of Bag of Holding interiors, spaces barely large enough fit a small pile of equipment. The largest, however, is Sigil.
Sigil is known as the city of doors, as it boasts the densest collection of portals known to sages. It occupies a nonplanar space that is exactly big enough to hold it – there are no walls around Sigil, for it is all that exists in its dimension. Races from all over populate it, and it is protected by a mysterious patron known as the Lady of Pain.
Creatures cannot originate from nonplanes – those who reside in them (or their ancestors) all came from somewhere else.