- Theodore Roethke
Also known as the Material, the Prime, the Mortal Realm is the axis around which the rest of the known multiverse spins. This iteration of Earth is primarily inhabited by humans, but many of the supernatural races--including dragons, giants, therianthropes, and the undead--also call this world home. Of the estimated 8 billion souls on Earth, ninety-nine percent reside in the Prime.
These five realms are bridges between the mortal realm and the five Pillars of Creation. Each one of these realms combines aspects of the Prime with their respective cosmic foundation. One feature of each of these five realms is that they have a fourth spacial dimension that stretches out from the Mortal Realm to their pillar. The closer one is to the Mortal Realm, the more the Supernal Realm resembles the Prime, while the further one gets, the more abstract, alien, and hostile it becomes.
The Elemental Domains, 'Aalam al-Jinn, Hundun. Chaos is a roiling realm where various primordial elements flare into being, incarnating the ideals of instinct and creation. Its human analogues are the sentient elementals known as jinn. The jinn are renowned for the ability to shape the very forces of creation through the art of wishcrafting. Over the centuries, the jinn have carved for themselves several nations out of the raw chaos, including the ifrits' Sultanate of Flame, the marids' squabbling oceanic fiefdoms, the slyphs democratic city-states, and the gnomes' Kingdom Under The Mountain.
Arcadia, Fairyland, the Storybook Realm. This realm incarnates the ideals of life and dreams. In this realm, everything is alive, from trees to rivers to the stars and planets to space and time to stories themselves. Those stories are faerie's human analogue, coming to life as the race we know as the fey. The fey create avatars known as characters to better act out their own personal tales, and engage in needlessly dramatic intrigue within the various fairy tale kingdoms and courts that dot the verdant realm.
The Netherworld, the Nightmare Land, Under the Bed, Closetland. Shadow is a dark and fading realm that incarnates destruction and nightmares. Because life naturally fears oblivion, the realm has also come to inadvertently incarnate fears, where every day is Halloween and every night is another horror story. Indeed, the human analogues of Shadow are the horrors, living incarnations of fears and phobias. The horrors were united under the Bogeyman, the legendary Lord of Terror, and are still ruled by the storied Parliament of Shadows he established. After the disappearance of the King Over Shadows, his Court of Nightmares has taken up the title of bogeyman in his honour, and they have carved great domains out of the shadows, each representing a specific primal fear, such as the fear of fire, the fear of disease, the fear of loss, or the fear of technology.
The Invisible Realm, the Axis Mundi, the Totemic Realm. This strange realm defies a lot of conventions, as everything here has a spirit, a soul, and sentience. It incarnates the cosmic principles of thought and hope. The region closest to the Prime holds the domains of the temporal spirits: the spirit of a particular river, or town, or street. As one travels deeper into the Spirit World, the spirits become more abstract: there are the spirits of the days of the week, of holidays, of animals and plants, of nations, and so on. Then, one enters the purely abstract domains, where one can find the spirits of say, math, or language, or emotion, before reaching the palaces of the Archetypes, the most fundamental of spirits: the Spirit of Law, or the Spirit of Nature, or the Spirit of Time, or the Spirit of Death. The spirits compose this realm's human analogues.
The Realm of the Dead, Stygia, Sheol, Purgatory. This bleak realm incarnates death and the inevtiability of fate. This is the only realm where the human analogues are entirely derived from the souls of other races, as, as far as any scholar has been able to tell, all the reapers in existence are mortals who died, and then chose to become a member of the enigmatic guardians of death. The exact workings of the underworld are poorly understood, as the reapers don't appreciate the living meddling in the affairs of the dead.
The Firmament, the Celestial Sphere. This is the realm that incarnates belief itself, the power of faith and magic. It surrounds all the other realms completely, and infuses them all. There are many small domains carved out of the Astral by various powerful entities, all of which orbit freely around the Mortal Realm like planets in a solar system. Some scholars even argue that the five supernal realms are merely stable astral domains created by the interactions of the cosmic foundations with the mortal realm. Powerful mages, and creatures from other realms, are able to create their own small domains within the raw potential that is the Astral. Some of the most notable Astral domains include:
The Outside lies beyond the Astral. It is the darkness beyond the stars, the void beyond creation, it is the time before the Big Bang and after the Pit consumes all of creation. The things outside defy the expected rules of science, of life, of existence itself, be they sentient colours or hateful mathematical equations or a martial art that will corrupt your body and soul.