In revising Engines & Empires and turning it into its own standalone RPG, it just seemed like the right move to separate it out from the Gaia setting. As I mention in the introduction to E&E's new edition, I invented Gaia for the sake of a fantasy novel; it just happened to be the setting that was on my mind when I was originally writing E&E.
But Gaia wasn't even a steampunk setting to begin with. The whole point of Gaia, as originally conceived, was a fantasy world ruled by an absolutely ridiculous variety of non-human races, with lots of magic and no technology, and with no humans whatsoever. To make that work as a game setting, I had to advance the timeline by thousands of years, introducing the "Third and Fourth Ages" of Gaia's history, making invading humans commonplace; and to make it work as the setting for E&E, I had to bring the technology level up to something approximating Earth's 19th Century.
Now, all of this invented history is largely preserved in the new World of Gaia guidebook that I'm quickly churning out here. I needed to crank out four parts for this book:
1. An introduction to the setting and an overview of any rules needed to play E&E games set in Gaia.
2. A new description of Gaia in general and the lands of Arcadia in particular.
3. The maps and descriptions of Arcadia's nations.
4. An introductory adventure module.
I've now finished writing parts 1 and 2. Part 1 was pretty easy, since I've only just finished writing E&E, and the only rules you need to add for playing in Gaia involve elevating a bunch of weird-ass demi-humans up to the level of full player-character options. So all of Gaia's odd races—elves, fays, gnomes, hán-folk, goblins, ogres, merrows, sylphs, fauns, and centaurs—get full write-ups; and about half a dozen less common races get tossed into the mix as alternative options too.
Part 2 was half copy-paste-edit all the historical material from the old Campaign Compendium (I just needed to make a few tweaks to help smooth over the wrinkles between E&E's new cosmology and the origins of the fays/sidhe), and half writing up some new material. This was pretty necessary: I never gave any real treatment to religion in the old guidebook. So I've found myself these past few days in the curious position of having to invent a new fantasy religion, and moreover of making sure that it was different from what I'd already used before in the Ælyewinn setting and when I've run games set in Færith.
Ælyewinn uses a straight-up fantasy religion that I invented whole-cloth as I was dreaming up the setting. It's pretty simple and straightforward: a mother goddess and her five children who serve as deities of earth, fire, wind, water, and darkness and also patrons of the common fantasy races. In Færith, I've just tended to throw around slightly modified European polytheism with the serial numbers filed off: the Celtic pantheon for the elves, the Norse pantheon for the dwarves, and the Greco-Roman pantheon for the humans. It works well enough.
But for Gaia, I wanted to do something a little different and quirky. I want it to have a very European vibe, but polytheism doesn't quite fit, and a straight-up knockoff Christianity is too boring. So I went and shamelessly cribbed from those oft-cited "alternative monotheisms" which are occasionally floated as historical "what-ifs"—as in, "hey, wouldn't it be weird if Zoroastrianism/Gnosticism/Mithraism had taken over Europe instead of Christianity?" They're just similar enough to work the way they should (meaning, to function in the setting as reasonably monolithic religions), but they're also just different enough to feel exotic and fantastical.
It is shameless? Unoriginal? Cultural appropriation?
Yes to all three. But then again, the World of Gaia setting is basically Cultural Appropriation: the Tabletop RPG, so I'm pretty much okay with it.
Anyway, that just leaves parts 3 and 4. Part 3 is again something of a hack-job, just cut-and-paste, edit for the formatting and kerning, change around a few names where I need to (mainly to account for the fact that E&E now uses goblins in place of dwarves, dwarfs in place of halflings, and gnolls in place of orcs—it's the demi-human species shuffle!).
And as for part 4, well, I already wrote and published a basic E&E adventure once; it's going to get a bit of a face-lift (and a new map) here. But most of this will just be rote, mechanical transcription. Easy-peasy-3.1415926.