Introduction

I'm realising that this homebrew is getting way beyond the usual DnD expectations and it's a different setting, for which quite frankly you guys haven't signed up on. But it is what I want to dm and even though I'm happy to accommodate requests and ideas and even change certain aspects, the very basics of it won't change.

So what is it and what is it not? It is NOT the Forgotten Realms. It is NOT Tal'Dorei. It is NOT like most medieval fantasy homebrew worlds. It is something else. There will be the same basic building blocs of DnD - fantastical locations, intrigue, combat, magic, quests, the ability to shape the world by one's actions - it will use the same classes, mostly the same races and all game mechanics of 5e

Some parts of it will have a different flavour. More Eberron, than FR. But also not Eberron at all.

1. A Shattered World
The biggest change is the world itself. Instead of being a continent or flat world with many continents, this "world" will be made up of many floating continents and islands called floes. These floes move around a tiny star, which forms the core of the system. The floes being grouped in a number of shells or rings or belts, with varying distances from the core. Each moving on their own, often lonely, path on the Drift.

2. Floes Are Small
The majority of floes are more like islands of various sizes than true continents. Some are small enough to be more like ships. And with such small sizes comes a scarcity of resources.

3. Travel Is Difficult
Gravity works in mysterious ways and it affects the stability of reality. What this means, is that landmasses have bubbles of safety around them. Even though you can see another floe, that does not mean that you can reach it. You cannot simply fly over unless the bubbles of safety - the gravity wells - connect. It is then that travel between places is possible via various means of flight. This also means that there are windows of opportunity. Your floe might connect to another for a while, allowing you to explore or trade or do whatever. But after some time, they will drift apart again. This is a major part of the game, as the small, stable and inhabited floes can interact with larger, unstable and dangerous ones. There are ways to circumvent the limitations of travel, but they are rare and should be meaningful to acquire. Each coming with their own limitations. One of them is bound to the insectoid Kentaki. Them being able to traverse the dangerous vacuum between the gravity wells; finding the few strings that connect them. And controlling this monopoly with a firm hand. BUT: It is not a space game.

4. Gravity Is Reversed
Things do not fall towards the core, they fall away from it. Which means that unlike our universe, people stand on the inside of the shell; looking up towards the core and down towards space. This brings a number of changes to everything. The curvature of the shells, means that one can look up to see the other side of the world - if there wasn't a core and a bunch of shells blocking the view. But one can see the horizon disappear into what could be described as looking at far away mountains. Sort of like the ring from Halo. This visibility is limited, but it is a thing to remember.

5. Resources Fall
This is a world of plenitude and scarcity. Light and Water are the two most important resources and they all fall from outwards. Which means that they will be scarce for those below. And so will everything that relies on them -> food. That does not mean that player characters will have to constantly hunt for food, but that the lack of resources will be a major theme that guides the events of the game. To make this work within the rules of 5e, spells and abilities that simply bypass these things will be limited in their use, or incredibly valuable, instead of a back thought.

6. The Night Is Full Of Terrors
The Light is what keeps things safe. And the darkness brings untold horrors. Some embrace it, but it is a risky business.

7. There Is No Pantheon Of Gods
There are no gods that meddle in the affairs of mortals. There is faith and divine power that can be used by people. Divine Intervention and Divination and Commune all work, but they are not targeting quasi-humanoid beings of power, but aspects of power itself. There are religions that attribute character to these aspects, but they are more like our world, than the meddling gods of the Forgotten Realms. There are beings of power that work as patrons and can give power akin to gods, but they are not the same as actual gods.

8. Besides Magic And Faith, There Is A 3rd Source Of Power
Following the ideas of Eberron and many other fantasy and steampunk settings, there is some technology existing in this setting. It is not electricity or steam, though, but the very essence of the world. It is the peculiar living metal that is affected not by the reversed gravity, but is instead pulled towards the Core. It is this material, present in all life forms and found inside all floes, that keeps things stable. And it has been used to fuel a variety of biotechnical inventions. Things like the gliders used by exploring parties, but also a variety of weapons and other creations of the artificers of this world. And it is poisonous.

To simplify: This is not a Sci-Fi campaign. It is firmly rooted in fantasy and will have magic and all the usual stuff. It will be akin to sea faring / island hopping. But there will be long times of downtime between the adventures. Time for the characters to grow; in the limited space of their floes.