Good idea, Jiro. Something happens in Eizon that causes the Crystal to return and shatter, scattering itself across the world. All crystal pieces could originate from The Crystal. Also, the Crystal Collapse could be a major catalyst that started the past war between Amano and Baroke.

This is assuming a lot but if you guys want to roll with it... we can say that Humans originally lived on Amano where the Moogles do now and that they were the ones at war with the Dwarves on Baroke but were persuaded to move away from the Dwarves by the peace-keeping Moogles. ?