Ar Tonelico 3’s world – Sol Cluster is pretty much dominated by β-class Reyvatail which are the ruling class. They reside in the country of Clustania. The ideal world to them consists only of Reyvateils and purified humans. Purified humans are inferior to the Reyvatails. The rest of the humanity stays in the land of 大牙 (Great Fang)?. It is a pretty dark world as compared to the previous Ar Tonelico series imo - The Banzai Effect.
The official site has launched (yay music,) but The Banzai Effect has been trickling out pearls of information about the characters and system, so make sure you check that out.