@lain also not exactly Christianity, more like abrahamic religion in general. Most of the stuff they use is old testament which is more or less the same across the big 3 just called different stuff. Anything extra they use is usually apocrypha, but sometimes it'll go even deeper into what one could consider Jewish/Christian "mythology." Haven't really seen the same thing for Islam but I can only assume it is because that's deemed to be much more offensive.
I'd like to see more games that have themes of alchemy too. Not just like crafting game mechanics but the whole belief and its practitioners secrets.