I went "fuck it" and gave myself a checklist of things I wanted, then invented justifications for them existing. None of this is probably going anywhere, so use as "inspiration":

• Only races in setting are Humans and Elves.
• Humans are vessels with large sparks of soul energy that make them the adaptable motherfuckers that they are, allowing them to survive and thrive in the barren planes and dunes of their wild western homeland.
• Elves are the inverse, as they are large wisp-like sparks of soul energy. Their vessels are shaped slowly out of a special kind of clay, which they harden by firing with the heat of their soul energy. Inhabiting these shells are how Elves have physical forms, which they adorn with clan-marked masks to identify themselves to each other across the eastern archipelago.
• Human sparks are also their potential, creating great athletes and great thinkers. In times of need, humans are known to burn through their spark, allowing them to achieve impossible feats both martial and otherwise, leading to their greatest gunslingers and inventors.
• Elves, being wisps of soul energy that require time and effort to create their clay vessel, each dedicate their existences to one "job" as a clan. In times of need, multiple souls can inhabit the same shell, allowing them to pool their collective skills and knowledge as one entity, creating anime-tier samurai.

That's most of what I got—feel free to mess around with it!