Cosmology Overview

Calcaria is the centre-piece of a multiverse filled with all manner of strange and wonderful sights. From the goddess Eriu's domain of Yggdrasil, the world tree, to the melancholy Twilight Realm of Badb, the most bizarre of all is that which lies at its centre: The common world of mortals, known as the prime material plane.
The cosmology of Calcaria has been researched, studied and scrutinised over centuries by scholars of all type and races. None have come so far as Muldefix the Elder however, who spent decades studying the domains of the gods, the elemental planes and the ethereal and astral. From him stems the currently accepted model of the Aeternum and the alien and frightening things that reside in it.
Beyond the Material Plane, the various planes of existence are realms of myth and mystery. They’re not simply other worlds, but different qualities of being, formed and governed by spiritual and elemental principles abstracted from the ordinary world.

The Inner Planes

Invisible but binding around Material Plane are the Shadowfell and Feywild, mirror planes who resemble the absence and abundance of emotion respectively. Through these two planes it is thought that a balance is achieved on the prime material, Calcaria.
Beyond the mirror planes and the prime material lies the omnipresent Ethereal Plane, which binds and connects all the Inner Planes, including the plane of judgement; The Long Shadow.
Below the material plane and connected through long forgotten, mile deep tunnels to the Labyrinthian lies the Infernum. Those scholars who posit that Calcaria is a round globe further believe the Nine Hells are the first layers before one would reach the core of the sphere. Last but not least are the Elemental Planes that cross and surround each other as well as the prime material:

• Plane of Earth
• Plane of Fire
• Plane of Water
• Plane of Air

The Outer Planes

Muldefix also explored the eight greater domains that are more or less physical but require substantial magic to reach. These planes can only be reached through the transitive plane of the Astral, or plane of dreams. (Included are the lesser domains that abide by the greater domain's laws)
I. Sanctum, Danu's domain
a. The Holy Furnace, ruled by Goibniu
b. Eden, ruled by Epona
c. The Celestial Host, commanded by Morrigan

II. Jericho, Luna's domain
a. Sea of Tranquility, ruled by Dagda
b. Sea of Serenity, ruled by Aengus
c. Sea of Fecundity, ruled by Nuada

III. Tethys, Eriu's domain
a. Elysium, ruled by Macha
b. Duat, ruled by Arawn
c. The Beastlands, ruled by Flidais

IV. Aimsir, Taranis' domain
a. The Rook, ruled by Mebd
b. Stormreach, ruled by Lugh
c. Aigéan, ruled by Lir
d. Tine, ruled by Aed

V. The Twilight Realm, Badb's domain
a. The Gray Waste, ruled by Umbra
b. Sea of Blood, ruled by Cromm


VI. Bytopia, domain of Aine
a. The Rose Garden, ruled by Rosmerta
b. The Deep Well, ruled by Trinor
c. The Great Stage, ruled by Onuava

VII. Liberis, domain of Lero
a. Pseudo, ruled by Oghma
b. Arcadia, ruled by Niskus

VIII. Calypso, domain of Gwydion
a. Clover, ruled by Ceridwen
b. Skoll, ruled by Gywnedd
c. Vesuna, ruled by Gráinne

Demiplanes

Demiplanes are small extradimensional spaces with their own unique rules. They are pieces of reality that don’t seem to fit anywhere else. Demiplanes come into being by a variety of means. Some are created by Spells, such as "Muldefix's Demiplane", or generated at the desire of a powerful deity or other force. They may exist naturally, as a fold of existing reality that has been pinched off from the rest of the multiverse, or as a baby universe growing in power. A given Demiplane can be entered through a single point where it touches another plane. Theoretically, a Plane Shift spell can also carry travellers to a Demiplane, but the proper frequency required for the tuning fork is extremely hard to acquire. The gate spell is more reliable, assuming the caster knows of the Demiplane.

Type

Metaphysical, Divine