Reimian Empire

That's exactly how I would describe it.

Having lost the last drops of his patience, Dillion Dendark rushed to insert the stones into the openings according to the theories of Castor L. Celena. After several unsuccessful attempts and subsequent battles, easily won thanks to the effectiveness of Aiyano Yamagami's external barrier and the combat skills of the group's warriors, the left, right, and central doors finally opened.