From House of Hozz
The cosmos is very ill defined at the moment. Much of this will not be revealed directly in the stories, but we should have a concept of it, in order to make everything harmonious.
- What Fantasy and Sci-Fi elements exist?
- What races/factions are there?
The Fair Folk (fairies) exist, and are a visible and tangible influence in the world. They are the source and keepers of all magic. Space flight is possible using this magic, so there are several cities on other worlds. However, the fairy are fickle, so transport and communication between these worlds is not fully reliable. The fairy are also tied to plants and fungi, so they mainly live in huge forests, which they also cultivate. Humans also have technology (What era? No explosives? No major combustion fuels?) and have many large cities which the fairy shun because of their dearth of plant life.
This cosmology would allow for both the fantasy and science-fiction arch-genres, as well as a continuum between them and the flexibility to tell almost any type of story.