It was more than a million of years ago. Kaschia was a great port city where goods and trades travelled to. It was the most popular and powerful kingdom. Something happened.
And Kaschia was becoming smaller and more wicked. It was nicknamed "City of Evil" before Hyoji destroyed the universe and rebuilt it? But what was it that created the evil? Kaschia is now a deserted island where spiritual people enter. You have to be very pure to enter Kaschia