The planet is originally belonged to the Cetra (ancients), an itinerant race. They migrate in, settle the planet, then move on. At the end of their long, hard, and harsh journey, they'll find the Promised Lands and supreme happiness.But those who dislike the journey appeared. They stopped the migration, built shelthers, and elected to lead an easier life. Those took that which the planet and the Cetra gave without giving back one whit in return. And that is human ancesters.
Long ago, destruction struck this planet. Human ancestors escapes and survived because they hid. The planet was saved by sacrificing the Cetra. Then human ancestors then increased.
Then, an ancient named Jenova was found in the geological stratium 2000 years ago. (the Jenova Project)
The project was started by Prof. Gast. They want to produce people with the powers of the Cetra. Sephiroth is then produced.....