Demon World

It is revealed that the world is indeed split into two instead of Demons having conquered the Human world within the last 30 years.

Ancient Treaty
We shall make a treaty as follows:
 * 1) Humans won't hunt Demons anymore.
 * 2) Demons won't hunt Humans either.
 * 3) The world they live in is divided in two.
 * 4) Crossing the border between worlds is forbidden.

Some humans were "left behind" probably to farm.

Trivia
The demon world is theoretically divided into 4 areas as per Minerva's pen with Gracefield House as the origin point, they are namely "A", "B", "C", "D".in a clockwise manner.