Regarding the World and the Planes
At the center of the material world is Heaven, an infinite expanse contained within finite volume. Here is the celestial firmament, and a mixture of emptiness, and innumerable objects of stupendous size and separation.
Outside of Heaven is the Sky, the realm of air, cloud and flying things.
Outside of the Sky is the Earth, the realm of solid things. Here are the oceans, mountains, and the multitudes of walking beasts.
As one delves beneath the Earth's surface, things grow hotter and more pressurized, crushed between a great outward force pushing inwards, and an inward force pushing outwards. Matter undergoes several phase shifts as it grows hotter and denser. However, earth is does not possess infinite volume. In the inverse of heaven, it is a finite volume stretched across infinite space. Paradoxically, despite matter being under very high pressure, its volume becomes greater with depths.
At the very outer edge of the earth, existence is stretched thinly, like diffuse smoke or a sheer gauze. This is imperceptible to a material observer, and serves functionally as an 'edge of the world' for the material plane. However, things not native to our world's material reality can be found between the webbing of diffuse matter here, caught at the outer fringe of our reality. Here is the jetsam of other worlds and ancient forgotten things. This derelict, lost realm is known as Multor.
Outside of Multor, things grow stranger still. Physical reality becomes almost infinitely thin, and there is a vast abyss known as the Beyond. While it is infinite and unbounded in all directions, distance is meaningless outside of physical reality.
There are other worlds, dimensions, and possible existences outside of the 'Beyond', but they are inaccessible to any arcane or conventional means of transportation.
However, the material plane is not all that there is. Overlaying it and occupying the same area is the parallel aethereal plane. All things can be classified into either matter or aether. While stone, air and water are purely material, thoughts, dreams and magic are purely aethereal. Many animate things are a mixture of both: just as humans have material forms, so to do they possess aethereal spirits. This is true to a lesser extent for all living things and the countless varieties of enchanted matter that exist.
The Dream or 'Ideal' plane suffuses the material plane, being formed of the collective thoughts of all sentient things. It is here that magic is wrought, and this power is what the gods use to shape reality.
Ley networks interconnect the aethereal plane, allowing for both great extended range of magic and communications, as well as providing a means of transportation for magic-users. The ley network is one of the very few ways to leave the material plane, although for all but the most powerful or magically adept, doing so is a death sentence.
The Obscuring Mists serve as an insulation, of sorts, for the Ley networks and the Ideal plane, shielding them from the aethereal realms of Multor and the Beyond.
Multor, not just being a physical place tangled in the fringes of the material plane, is simultaneously an aethereal realm. Thus, it is one of the rare places where purely material and purely aethereal things can interact. Here, one can be assaulted by their own manifested fears, or walk through a waking dream.
Finally, the Beyond is, just like its material equivalent, an unending, expansive abyss. However, it is not entirely empty. Here, there are strange abandoned dreams and forgotten concepts, fragments of dead gods past and other isolated shards of Multor. The most famous of cosmic jetsam to be found in the Beyond is the erstwhile prison of Nital.
Finally, we come to the topics of worlds within worlds: pocket dimensions, magical realms, demiplanes, and inner worlds.
Pocket dimensions are infoldings of the world, so named due to the fact that they are the dimensional equivalent to sewing a pocket into the fabric of reality. They are made of the same stuff as the world, and follow the same laws. As such, they require relatively little maintenance once created. Pocket dimensions are often hidden, or only accessible through certain openings. The Tower of Exiles and Kross' world are prominent examples of pocket dimensions.
Magical realms (or magical dimensions) exist wholly in the aether. Here, the physics of the outside world may be entirely ignored, and can be altered at the whim of its inhabitants, or those who are in control of the realm. Magical realms must be actively maintained, as without thought, they cease to exist. Hell is a prominent example of a magical realm, or magical dimension.
Demiplanes are miniature worlds, wholly separated from the main world. Thus, they are still material, like pocket dimensions. However, rather than being hidden infoldings of the primary world, they are entirely distinct places, separated by great distance from the primary world. As they are part of the material plane, they are subject to the same physics as the rest of the world. As most demiplanes exist in places that are inimcal to life, demiplanes tend to require active maintenance, to maintain temperatures, pressures, air and gravity. Tar Vash'eth is one of the best known demiplanes, being hidden far out into the Beyond.
Inner worlds exist in the sky and heaven, scattered across the celestial firmament. They are entirely part of the primary physical reality, though they are often hidden by the vast distances that are compressed into the expanse of heaven. The moon is an example of an inner world, and it could be argued that the great floating stones of Phusikkes also count as inner worlds, given that many of them are suspended above the clouds in the sky.
-Mandas
At the center of the material world is Heaven, an infinite expanse contained within finite volume. Here is the celestial firmament, and a mixture of emptiness, and innumerable objects of stupendous size and separation.
Outside of Heaven is the Sky, the realm of air, cloud and flying things.
Outside of the Sky is the Earth, the realm of solid things. Here are the oceans, mountains, and the multitudes of walking beasts.
As one delves beneath the Earth's surface, things grow hotter and more pressurized, crushed between a great outward force pushing inwards, and an inward force pushing outwards. Matter undergoes several phase shifts as it grows hotter and denser. However, earth is does not possess infinite volume. In the inverse of heaven, it is a finite volume stretched across infinite space. Paradoxically, despite matter being under very high pressure, its volume becomes greater with depths.
At the very outer edge of the earth, existence is stretched thinly, like diffuse smoke or a sheer gauze. This is imperceptible to a material observer, and serves functionally as an 'edge of the world' for the material plane. However, things not native to our world's material reality can be found between the webbing of diffuse matter here, caught at the outer fringe of our reality. Here is the jetsam of other worlds and ancient forgotten things. This derelict, lost realm is known as Multor.
Outside of Multor, things grow stranger still. Physical reality becomes almost infinitely thin, and there is a vast abyss known as the Beyond. While it is infinite and unbounded in all directions, distance is meaningless outside of physical reality.
There are other worlds, dimensions, and possible existences outside of the 'Beyond', but they are inaccessible to any arcane or conventional means of transportation.
However, the material plane is not all that there is. Overlaying it and occupying the same area is the parallel aethereal plane. All things can be classified into either matter or aether. While stone, air and water are purely material, thoughts, dreams and magic are purely aethereal. Many animate things are a mixture of both: just as humans have material forms, so to do they possess aethereal spirits. This is true to a lesser extent for all living things and the countless varieties of enchanted matter that exist.
The Dream or 'Ideal' plane suffuses the material plane, being formed of the collective thoughts of all sentient things. It is here that magic is wrought, and this power is what the gods use to shape reality.
Ley networks interconnect the aethereal plane, allowing for both great extended range of magic and communications, as well as providing a means of transportation for magic-users. The ley network is one of the very few ways to leave the material plane, although for all but the most powerful or magically adept, doing so is a death sentence.
The Obscuring Mists serve as an insulation, of sorts, for the Ley networks and the Ideal plane, shielding them from the aethereal realms of Multor and the Beyond.
Multor, not just being a physical place tangled in the fringes of the material plane, is simultaneously an aethereal realm. Thus, it is one of the rare places where purely material and purely aethereal things can interact. Here, one can be assaulted by their own manifested fears, or walk through a waking dream.
Finally, the Beyond is, just like its material equivalent, an unending, expansive abyss. However, it is not entirely empty. Here, there are strange abandoned dreams and forgotten concepts, fragments of dead gods past and other isolated shards of Multor. The most famous of cosmic jetsam to be found in the Beyond is the erstwhile prison of Nital.
Finally, we come to the topics of worlds within worlds: pocket dimensions, magical realms, demiplanes, and inner worlds.
Pocket dimensions are infoldings of the world, so named due to the fact that they are the dimensional equivalent to sewing a pocket into the fabric of reality. They are made of the same stuff as the world, and follow the same laws. As such, they require relatively little maintenance once created. Pocket dimensions are often hidden, or only accessible through certain openings. The Tower of Exiles and Kross' world are prominent examples of pocket dimensions.
Magical realms (or magical dimensions) exist wholly in the aether. Here, the physics of the outside world may be entirely ignored, and can be altered at the whim of its inhabitants, or those who are in control of the realm. Magical realms must be actively maintained, as without thought, they cease to exist. Hell is a prominent example of a magical realm, or magical dimension.
Demiplanes are miniature worlds, wholly separated from the main world. Thus, they are still material, like pocket dimensions. However, rather than being hidden infoldings of the primary world, they are entirely distinct places, separated by great distance from the primary world. As they are part of the material plane, they are subject to the same physics as the rest of the world. As most demiplanes exist in places that are inimcal to life, demiplanes tend to require active maintenance, to maintain temperatures, pressures, air and gravity. Tar Vash'eth is one of the best known demiplanes, being hidden far out into the Beyond.
Inner worlds exist in the sky and heaven, scattered across the celestial firmament. They are entirely part of the primary physical reality, though they are often hidden by the vast distances that are compressed into the expanse of heaven. The moon is an example of an inner world, and it could be argued that the great floating stones of Phusikkes also count as inner worlds, given that many of them are suspended above the clouds in the sky.
-Mandas