The vast land in the skies was created as a shelter from the predicted flood.
Some escaped from the disaster into the skies, while many left on the surface perished and lost everything in the flood.
Even after the flood has subsided, and living on the surface was made possible again, those who moved to the land in the skies never returned.
That was the birth of two worlds - the Heights and the Depths.
A man-made island in the skies. Life in the Heights is under the control of the "Temple", a government that also decides on the people's partner in marriage. Peace is maintained in the Heights by sending criminals to the Depths.
It is a world built by those who miraculously survived the flood. Without the concept of country or a government, each district is governed by a person of power within its land. Unlike the Heights, the Depths has developed its own unique mechanical culture.