Kyvan creates Oreba.

He creates a first generation of Crystali in Moonvale to give them fertile land and mild winters. He spends a lot of time teaching them and interacting with them. This is when all the most accurate and true information was logged, and the remnants of that can still be found in present generations. (Like artifacts, old books, etc)

They thrive under Kyvan as their kingly god.

Kyvan is seen less often. He confides in a select few that his time on Oerba is over. The select few pass on his message and all remains relatively peaceful.

Population has spread to all of Oerba at this point. Cities, economies and a monarchy is Built. People still somewhat beleive in him, but it becomes more of a 50/50 situation where some communities beleive while others do not.

Things become a little rocky and conflicts start to happen over land/resources. The Monarchy is still pretty stable but people are definitely starting to get greedy.

Not many know about Kyvan, let alone beleive in him.

The Queen is corrupt. Most of the resources are being funneled into Sashai where the grand capital is. The Queen knows of Kyvan and wants all his power to grant herself eternal life/power.

Most people don't know or care about Kyvan. They beleive that kind of power is a myth, but knowledge of him is very much still present, although in fragments. Mostly in descendants of the select few he confided in when he took his leave the first time.