This world has undergone startling historical changes. With the "Great Annihilation" as the turning point, the entire world—and even its fundamental rules—underwent a dramatic transformation, so much so that the deep sea era that followed the Great Annihilation and the Order era that preceded it can almost be regarded as two entirely different "worlds."
Yet even so, some people persistently organize the historical materials passed down after the Great Annihilation, attempting to sort out the true appearance of history from the fragmented and even contradictory archives of various city-states.
Unfortunately, perhaps due to a thorough severance of transmission or the contradictory records of the city-states being too chaotic, people have not been able to find a more complete and credible historical account of the time before the Great Annihilation.
No one knows what the world of the Order era was really like.