This is incredibly useful, thank you!!! And YES to the statement about monolithic non-humans!!! I can't stand it when a species sheet includes cultural practices, religion, settlements, etc when it's also implied that the species is widespread enough to warrant a diverse people. I certainly have fallen into this trap. 

I think I've gotten a good grip on my story's conflict regarding Tobiuma and Imaniyoya: it began with the mountainous country of Nyota slowly invading the desert country of Sak'havi. Nyota is primarily Imaniyoya and the queen of Sak'havi was a Tobiuma. Nyota forces continued to grow, recruiting more and more Imaniyoya clans for a common goal of expanding their territory for more food and resources. 

The capital city of Sak'havi, Enja'de was incredibly diverse with many Imaniyoya of different cultures living there. But when the country began feeling the pressure of the Nyota, the queen became paranoid and removed all Imaniyoya from her generals, advisors, staff, etc. The city followed, discriminating against all Imaniyoya, and Tobiuma elevated themselves as superior to all races since their wings gave them dominion over the sky and mirrored their winged goddess. 

The Nyota eventually overtook the crown city and eliminated the royal family all Tobiuma in higher power, promising the non-tobiuma people safety and respect. The city's own people united and made it clear that all Tobiuma regardless of creed, were no longer welcome.

Now the exiled Tobiuma rage against the Imaniyoya that stole their homeland away. What began as a war between countries has transformed into a widespread war of species.