Human World

The Human World is a realm that coexists with Demon World where other non-Grace Field House related humans are currently residing at.

In Chapter 173, Peter told Emma that the things that the demons were doing to them are the same to what humans are doing to each other for a very long time, even though humans do not eat humans.

After entering the door, the Grace Field and non-Grace Field children were teleported on Area 01, the former United States of America.

It is revealed in Chapter 179 that between 2020 and 2030, the human world was ravaged by disease, epidemics, food shortages, abnormal weather conditions and world war. In an effort of reconstruction, all national borders were abolished, making one huge nation.

The current Head of the Ratri Clan for the Human World is Mike Ratri.

Children and other humans from the farms wish to go to the human world in order to live at peace without demons.

History
Millennia ago, before the construction of plantations, both demons and humans shared the same world, which led to frequent hunting of humans by the demons. Some humans soon after did the same, while the rest worshiped them out of fear of getting eaten. This became a continuous cycle as both sides killed and feared one another. After countless violent wars and massacres, a clan of humans called the Ratri family stood up to the demons and made a treaty known as The Promise.

The Promise declared that "humans and demons are restricted from further hunting." Afterwards, the world was broken into two — one side belonging to the demons while the other belonging to the humans.