[Volaire] City of the Stars

Fueled and fed and fought over by a hundred worlds, dozens of species gather to live, work, compete, love, and finally die. The shining jewel of the Rings of Mondria, the asteroid cluster of Volaire sees countless ships sail in from other stars. A swirl of plots, factions, and sedition that leaves even the hidden cults’ heads spinning. Tattooed paladin wizards enforce the will of the Sikato Church, spies trade secrets between merchants and clergy and nobles alike, and orcs scrawl anti-telepath slurs on buildings. Adventurers come, drawn by Volaire’s wealth and the factions at play for power and influence. It is a place where there is much opportunity for a sharp blade, a quick mind, as well as constant danger.

What is Volaire? Volaire is the focal city for a custom fantasy setting where travel across the Tapestry is an integrated trait of society. Aboard flying ships, ala Spelljammer.

What is the Tapestry? It is the setting's colloquial term for outer space. I feel it's important that the in-universe natives don't use the term "space" because their space isn't our space.

How is space not space? Because it's not empty! This is a fantasy setting, with wizards and dragons, so physics is already on vacation. In Volaire, physics largely follows the same rules, except the phrase "nature abhors a vacuum" is taken to its logical extreme. The entire void between worlds is, generally, breathable atmosphere.

Can a bird fly to the moon? Depends. African or European? But more seriously, probably not. I'm not changing the distances between celestial bodies, so it's still literally hundreds of thousands of miles between a planet and its moon. Your typical bird is likely to die of starvation.

What about gravity? Ah, now there's a question with some weight to it. Gravity isn't changed in this setting, broadly speaking. Obviously it's adjusted a little to handle the atmosphere. You otherwise still experience microgravity in orbit, orbital mechanics of planets largely follow the same rules, people jump farther on smaller worlds, etc.

What rules/system does this setting use? Strictly speaking, the material I'm providing is system-agnostic, but it was originally designed for a the E6 variant of D&D 3.X. So while it can be used with essentially any fantasy system, it will experience some internal inconsistencies the farther you stray from the original. So, while it's absolutely compatible with 5E, adjustments need to made around the fact the setting (for PCs) does not allow for planar travel, interplanetary travel & interplanetary communication, and resurrection magic is unavailable.

Planar Travel is probably the most important restriction. The setting allows for summoners and warlocks to function, so calling upon the other planes for energy or even minions is permissible. But exploration should be about going to other planets, not other dimensions.

Related to the fact exploration in the setting should be about going to new worlds, interplanetary travel is equally verboten. Even spells such as teleportation circle should not allow for distances past a world. I would allow for major infrastructure projects to create something analogous to star gates, but those should be considered major architectural projects just to be able to reach that planet's moon, maybe another planet within the same solar system if you're wanting a particularly large work. At the minimum, neither Volaire nor its host planet Mondria have any such gates.

Interplanetary communication was presumed unavailable in its original design, barring physically going to said planet with the message in your hand. Now, it can certainly be introduced, as I've done in my own campaign as a major plot point, but it's presence would be considered disruptive to the status quo. It's not something that should be introduced casually.

Cheating death with resurrection magic is probably the most flexible restriction on this list. The core conceits of the setting do not hinge on its absence, so any restrictions would be to enforce the narrative weight of death. I would personally use something akin to what's been used in Critical Role.