On Thesis civilizations have thrived for generations. The rich resources of the land have always provided for its inhabitants.
Those creatures eventually evolved into the noble human like inhabitants of Thesis today.
Except that this species is a species with Amnesia. They do not remember their beginning, their origin. They can only hang onto what they find.
A great calamity hit Thesis destroying the thriving civilizations. These civilizations were wiped out. Only a few survivors from the clans lived to pass down the knowledge they knew.
This wasn't enough. Relics, archiac items of the old world sometimes answers a few more questions.
Though that doesn't seem to be enough either to answer all the questions of what happened. It is up to you to uncover the whole or true story.