In the southeastern region of Hamlet Continent, there exist three nations collectively known as the "Three Major Southeastern Kingdoms". They are the Zhao Kingdom in the south, the Wei Kingdom in the north, and the Liang Kingdom in the west. Among them, the Zhao Kingdom in the south is the most powerful, with a population of 180 million its own citizens and a total of 40 million citizens from its vassal states. Next is the Wei Kingdom in the north, which has a population of 80 million. Finally, there is the Liang Kingdom in the west, with a population of 60 million.

Along the border between the northern Wei Kingdom and the southern Zhao Kingdom lies a sprawling snow-capped mountain range. At the foot of these mountains sits a lake known as the "Sacred Lake" — and this is the Mental Entity habitat referred to as the "Great Blockaded Region". The Great Blockaded Region is also the most dangerous known Mental Entity habitat on Hamlet Continent. Though there has been no "Outbreak" for a long time, people have still built high walls around the Great Blockaded Region as a precaution, to guard against and monitor conditions inside it.