Overview
The primary Exocosm world is a realistic extrapolation of Earth into the future and an investigation of possibilities based on current scientific knowledge. This is suitable for science fiction stories, however, in the fantasy genre more flexibility is available.
Various worlds that diverge from reality are swirling around in my head but a few possibilities are sketched out below along with various possible sources of inspiration. Perhaps they all lie in the same universe just like exoplanets in the real universe? Does this mean they all have the same underlying metaphysics?
Worlds
Amalgam
How different would life be if it used metal as easily as carbon?
Amalgam is a strange world where metal merges seamlessly with flesh and islands float in the sky. Life has evolved that is similar to Earth life in some ways and yet is so very different. Seemingly magical abilities allow communication from a distance, seeing in the dark, moving metal without touching and summoning lightning.
Inspiration: Airships, Alchemy, Electricity, Magnetism, Mirrodin, Radar
Erato
What would life on a flat world actually be like?
While a few lunatics hold the crazy idea that the world is round all educated people know the world is a flat disc. Around this disc orbit a Sun and Moon providing day, night, seasons and tides. Feudal kingdoms following different interpretations of the religion of the Silent One cover the world. In the absence of clarification wars and crusades are necessary to determine whose interpretation is correct.
Inspiration: Europe, Flat Earth Conspiracies, Middle Ages, Monotheism
Erebus
What if the arcane technology used to survive the harsh environment was actually causing the environmental change?
The dying world of Erebus is slowly freezing. Civilisation clings on in scattered volcano cities using the same arcane technology to survive that is also dooming their world. Raiders scour the wilderness taking resources from any unlucky travelers they encounter.
Inspiration: Climate Change, Dark Sun, Gunpowder Empires, Ice Age, Mad Max, Shadow and Bone (Netflix), Steampunk
Khora
What would space be like using fantasy pseudo-physics?
A nautical themed space-fantasy world formed from myriad planetesimals floating in the void. Civilisations develop aether ships using arcane machinery or flesh crafted void beasts to colonise and unite these planetesimals. On distant worlds alien minds are awakening and turning their many eyes to observe.
Inspiration: Automata, Biopunk, Dune (Frank Herbert), HP Lovecraft, Psionics, Space Whales, Spelljammer, Steampunk, WH40K
Koilos
What would living in a hollow world be like?
In a world without stars, the sight of distant lands fills the sky above. The Sun is perpetually overhead, evenly illuminating the land. Floating islands occasionally provide shade on a clockwork schedule. Travel between these continents and the other side of the world has been achieved with great flying machines starting an Age of Discovery.
Inspiration: Airships, Flying Machines, Hollow Earth, Mystara, Solarpunk
Panopticon
Can sufficiently advanced magic be indistinguishable from technology?
In a set of small connected planes at the centre of the multiverse, sits the city of Panopticon. The inhabitants’ mastery of the flow of aether through the world enables both “spells” and arcane devices. Portals lead to various suburb planes and outposts across a wide planar trading empire. At the centre of Panopticon resides a mysterious many-eyed entity that simply watches through all the portals, looking for something or someone.
Inspiration: Age of Sigmar, Carnival Row, The Light Ages (Ian MacLeod), Perdido Street Station and other Bas-Lag novels (China Miéville), Planescape, Shadow & Bone, Teslapunk
Pharos
Can a lighthouse mimic a sun on a flat plane?
On the flat world of Pharos titanic mystical lighthouses on impossibly steep mountains provide a cycle of day and night. The glimmering lights of the other lighthouses can be seen in the distance. In the cold dark regions between lurk hungry daemons eager to feast. Only the presence of the light keeps them at bay, though if that should fail…
Inspiration: The Great Ice Ball Earth Theory, Olbers’s Paradox, the Pharos of Alexandria, the Spire in the Outlands
Plendrix
Where does light come from on an infinite flat plane?
The world of Plendrix consists of an infinite flat plane containing crashing tectonic plates separated by glowing magma oceans. Gravity is constant above Plendrix, no matter how high you travel into the infinite skies. No sun or moons lights the land, instead the surface is lit by the omnipresent glow of distant magma bent back towards the ground by the force of gravity.
Inspiration: Fire Sea (Margaret Weis and Tracy Hickman), General Relativity, Minecraft, Plate Tectonics
Xungla
Can advanced fantasy societies develop by replacing the bronze age with magic?
A metal poor world that is limited to stone age societies. The use of magic allows a different path of development, not possible on Earth. Golems, elementals and the dead all provide ample “manpower” to compensate for the less efficient tools. Fleshcrafting is used to shape animals for labour, resources and even war.
Inspiration: Aztecs, Biopunk, Dark Sun, Polynesia, West of Eden (Harry Harrison)
Ysbyrd
What if the boundary between the worlds of the living and dead was less defined?
Death is not the end, it is just a transition from one state of being to another. Encountering ghosts and animated corpses is an everyday occurrence but are the dead revered or treated as a resource to be exploited? Advanced civilisations are built on arcane technology that extracts power from death but perhaps it has negative consequences too.
Inspiration: Bone Song (John Meaney), Dracula, Egypt, Ghostwalk, Lockwood & Co (Netflix), Wraith: the Oblivion