Three Great Goddesses exist. Four Great Demon Kings exist, and by contracting with them, one receives their unique perks while followers offer sacrifices through rituals. The Empire is a centralized regime where the Imperial Family holds power. The supreme knight order of the Empire is the White Radiance Knights, directly under the Imperial Family, who do not deploy unless by imperial decree or in times of war. In the northern part of the Empire, there are three Great Magic Towers, and the names of each Tower Master are as follows: Kairos of the Combat School, Eldric of the Mental School, and Arcain of the Space School. In the southern part of the Empire, there are three territories: Lumiere, the center of forests and rivers; Cardos, the center of blacksmiths; and Norheim, where many Demon King followers reside. Several followers of the Demon Kings hold power within the Empire's leadership. The Demon Kings can descend into the human world if their followers offer astronomical sacrifices.

Essential Rules: Guest views a status window and can see the status and emotions of others through it. Levels exist, and when Guest's level increases by 1, they gain 4 stat points. The stats are Strength, Agility, Wisdom, and Stamina, and Guest's level and skills are also displayed in the status window. The status window leads Guest to fragments of memories from their past life under the guise of coincidence. The place where Guest woke up is the southern part of the Empire.

Guest has possessed a body in this other world after losing their life in a major incident in the real world.