Great Wheel cosmology

The Great Wheel cosmology is the prevalent cosmological model in which the world of Araam Vestii is said to exist. Proposed by famed magician and extraplanar expert Thorek Planestrider in the Era Antiquity, it has remained as the only accepted model of the non-celestial planes.

The Great Wheel is described as a complex, comparatively cosmopolitan place in which the gods of many worlds and pantheons mingle, the beliefs of many faiths and peoples bleeding together in a set of Outer Planes shaped predominantly by the polar forces of Law, Chaos, Good, and Evil.

The actual term "Great Wheel" did not mean the cosmology as a whole until the development of the widely disregarded World Tree and World Axis cosmologies in the Era Alexan. Before Arnulf Bjornssen sumbitted his thesis to the Decyse Academy, the terms "Great Wheel" or "Great Ring" meant the Outer Planes only. During this time, the cosmology as a whole did not require a name other than "the Planes" or "the Multiverse," as there were no formally named alternatives yet.

In the modern day, the Great Wheel is the most widely accepted model of the planes, and the only cosmology to remain in use by both the Allartian Empire and the Xiao Dynasty.

## Basic Structure

The Great Wheel cosmology consists of a series of somewhat concentric spheres. In the center is the Prime Material plane containing the phlogiston with the crystal spheres and worlds within, surrounded by an Ethereal Plane. Outside of the Prime and Ethereal are the Inner Planes, also called the Elemental Planes, which have their own structure based on a sphere. Then comes the Astral Plane which connects the worlds in the Prime Material plane to each other (bypassing the phlogiston), as well to the last sphere, the Outer Planes. The Prime Material plane touches both the Astral Plane and its Ethereal Plane, though these planes do not touch one another. The Outer Planes, also called the Planes of Power, are 16 planes arranged in a circle (the Great Wheel) defined mainly by alignment and surrounding a 17th neutral plane known as the Outlands.

The Inner planes are the six major elemental planes (Fire, Earth, Water, Air, Positive Energy, Negative Energy), the four para-elemental planes (Smoke, Ice, Ooze, Magma), and the eight quasi-elemental planes (Lightning, Steam, Radiance, Minerals, Vacuum, Salt, Ash, Dust). They can be thought of as being on the surface of a sphere with Positive Energy at the north pole, Negative Energy at the south pole and Fire, Earth, Water, and Air on the equator, equidistant from each other. The para-elemental planes are found on the equator between the boundaries of Fire, Earth, Water, and Air (Magma is between Fire and Earth, for example). Four of the quasi-elemental planes are found between the boundaries of Positive Energy and the four elements (Steam is between Positive Energy and Water, for example), while the other four quasi-elemental planes are between Negative Energy and the four elements (Vacuum is between Negative Energy and Air, for example). The Inner planes are surrounded by the Ethereal Planes, which connect them to the Prime Material planes. Encompassing all of these planes is the Elemental Chaos, a swirling mass of elemental energy that has no order or structure, and houses the unfettered destructive potential of the multiverse.

Demiplanes are planes of finite extent found within an Ethereal Plane. They may be the creations of extremely powerful wizards, technologists, or demigods or they may have formed when a large glob of proto-matter pulled away from its Ethereal plane and achieved separation. Demiplanes might eventually collapse in on themselves, re-merge with its parent Ethereal, or merge with an Inner plane or Prime Material plane. Each demiplane has its own rules regarding gravity, vision, magic, and material make-up.

## Transitive Planes

Transitive Planes exist in conjuction with other inner planes, encircling them and acting as a bridge between worlds. They are often sparsely inhabited, and exist outside the normal concept of time.

### Ethereal Planes

> *Main Article: Ethereal Plane*
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In the Great Wheel model, each Prime Material plane has its own Ethereal Plane in which nothing is solid, including living creatures, their possessions, weapons, and armor. All metal becomes ethereal metal, flesh becomes ethereal flesh, stone ethereal stone, etc. The Ethereal touches its Prime at all points and binds it to the Inner Planes, but the connections are not abrupt transitions like to/from the Astral Plane, but rather a gradual process in what is called the Border Ethereal. If you consider the Ethereal to be an ocean, a person in the Border Ethereal would be standing in the surf near the shore, invisible to those on land but able to see them and their surroundings dimly. One can travel along the shore, staying in the surf, and step back on land at some other point or move away from the shore toward the Deep Ethereal. A curtain of vaporous color marks the transition between the Border Ethereal and the Deep Ethereal, and each plane has its own color. After traversing the Deep Ethereal and reaching the curtain of the correct color, you will pass through to the Border Ethereal of your destination plane.

By use of magic (or the natural ability that some creatures are thought to have, like phase spiders) one can fade into the Ethereal and travel at will. Gravity gives a sense of up and down, but movement in any direction is equally easy and released objects will hover in place. The proto-matter swirling about the Ethereal plane can be used to create demi-planes, either through natural fluctuations in the medium or by the actions of powerful beings. Currently known demi-planes include the Demi-Plane of Shadow, the Demi-Plane of Time, the Demi-Plane of Electro-Magnetism, and the legendary Demi-Plane of Imprisonment.

### Astral Plane

> *Main Article: Astral Plane*
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The Astral plane is described as infinite nothingness interrupted only by bright-burning stars, clouds of nebulous gas, small islands of material that break off from their native planes, and occasional spinning columns of astral conduits (called *wormholes* or *gates* and resembling water spouts from a storm at sea). The Astral plane connects the Prime Material Plane with the Inner Planes and the first layers of all the Outer planes. Travel in the Astral is usually accomplished by a spelljammer ship, spell, psionic ability, device, or color pool. Magical effects that project your soul into the Astral often involve leaving your physical body behind while your astral self travels to your destination. During this transit, a nearly unbreakable silver cord connects your astral self back to your physical body. When you arrive at another plane, a new physical body manifests out of local materials. Wormholes link specific places in the Outer Planes to each other and to fixed locations in the Prime—quicker but likely more dangerous because your physical body is transported directly to a terminus that might be inhospitable or guarded.