Here are a few (new to me) facts about Empyrea:
Frank Mentzer at the Q&A chat wrote:Most Settings are made by Game Companies, to promote and support their games. That’s normal. They’re also jam-packed with game-specific stuff, which is also normal.
Nobody has the extra cash to promote OTHER people’s games. But we’re all in the same Hobby, all sitting around tables and roleplaying, all fighting dragons and giants and such. The rule differences are minor, yet they’ve become walls, to some extent.
Settings don’t really HAVE to be system-specific. The crunch is, sure, and a lot of procedures, but for a setting that’s a small percentage of the whole.
That’s where we come in. Empyrea will be published for 10 game systems, and 8 of them are D&D or variations (Open Game License). Two aren’t: Runequest and Savage Worlds.
The others are D&D 5e, Advanced (1e/2e), BECMI, and OGL versions Pathfinder, Dungeon Crawl Classics, Castles & Crusades, Swords & Wizardry, and Hackmaster.
Each set will have ONE System Book with the crunch you select. You can add other System Books for minimal cost; don’t buy extra sets, most of them are the same.