Great Empire Where the Dragon Resides, also known as the Demon World, is a group of 15 nations ruled by the Emperor. The vast land is governed by the Four Heavenly Kings. It is the home of most demons.  Throughout the land, there are Demon Castles commanded by Demon Kings. The land is most a barren wasteland that is constantly attacked by monsters. The demons have an empire council to help evaluate situations and decisions. The capital of the Empire is the Imperial Capital (帝都, Teito). The Empire is at least ten thousand years old.
A group of genius architects and a guild of artisans who inherited their will and craft constructed the Empire's capital over the course of more than 1000 years.
In the past, the humans and demons had many wars between each other.
The Emperor suppresses the source of the New World at the Imperial Capital, while the people of the Empire take care of the spills.
- Shin Castle Southern Area 15