The Fifth World
The Cosmology of the Fifth World follows the Great Wheel model used in 3rd Edition D&D . The bulk of the game takes place on the planet Gaia, and Earth-like planet located on the Prime Material Plane. The planetary system is contained inside one of many crystal spheres suspended within a bright gas-like interstellar medium known to those who possess the capacity to traverse it as “phlogiston” or “the Flow”. Some games instead take place on the plane of Ravenloft (a unique demiplane nested deep within the Ethereal Plane and cut off from the rest of the multiverse by the will of the Dark Powers, featured in the eponymous Ravenloft setting), in the City of Sigil (a cosmopolitan metropolis located at the center of the planes, featured in the Planescape setting), and on the distant world of Athas (an ancient desert world ravaged by arcane magic, featured in the Dark Sun setting).
H1. List of Planets
There are 10 planets located in the crystal sphere in which the bulk of the action takes place, which orbit 2 stars. The first 9 planets comprise a heliocentric planetary system orbiting a main-sequence yellow sun (Sol), while the 10th planet is partially stuck in a temporal loop, having a unique 45⁰ orbit around a white dwarf star (Polarius) located at the edge of the crystal sphere.
A hot, rugged desert planet, littered with the runes of a once-great civilization.
A warm, lush world of mostly jungles and swamps, populated by a race of feline humanoids with psionic powers.
The main campaign world. Mostly analogous to real-life Earth, except it is visibly missing approximately 1/5th of the total landmass (apparently the result of a great cataclysm, as the remaining area is dominated by constantly raging storms and geological activity), and it is apparent that there was once a second moon which has been blown apart and now forms a ring system of small asteroids which periodically crash to the planet.
A cold world of icy tundra covered in toxic clouds, which hide the war-torn hells-scape beneath. Populated by two constantly warring races whose entire cultures are dominated by the idea of self-improvement through bodily augmentation; one through biological grafts, the other through cybernetic enhancement.
A gas giant with many moons, some of which are inhabited and the largest of which houses a space station catering to Wildspace travelers. Constant lightning storms ravage the surface of the planet, the largest of which is referred to as “The Great Purple Spot” (actually the location of Pandorym’s physical body).
7. Uranus / Caelus
A massive water world with a rocky, volcanically active core. Many fantastic aquatic sights to be seen (a Merfolk empire, giant whales and krakens, ancient Abolith cities, etc.)
A cold, dead ice world which hangs in suspension between the two stars. This is the home base of the Illithid Star Empire, which has an alliance with the Mi-Go (who bring them brains).
A world-out-of-time, which is locked in a recursive loop; it begins its orbit near the edge of the crystal sphere, rotates approximately 45⁰ around the white dwarf star, then vanishes and reappears instantaneously at its original position. Home to a hyper-advanced race of pan-dimensional beings who perceive time in a non-linear fashion, as well as the Time Vortex (a plot device for time travel).