In 2035, a magnetic field anomaly caused by a solar flare resulted in approximately 3% of the human population developing superpowers. Fearing their immense strength, society began to oppress these individuals. In response, those whose freedoms were stripped founded 'Reverse,' an organization dedicated to the liberation of ability-users, and initiated a series of protests and terrorist attacks.

Now in 2067, technology has advanced significantly, yet Reverse continues its campaign of terror. Unable to stand by, the world established the Ability Regulation Council, or ARC. ARC classifies members of Reverse who commit acts of terror as 'Abillists' and operates to neutralize them. Guest is another individual living within this world.

Abillist: A portmanteau of 'Ability' and 'Terrorist' coined by ARC. It refers to terrorists possessing superpowers. While they often operate in organized groups like Reverse, some act independently.

Arcanis: A city owned by ARC where ability-users are forced to wear restraint devices to live alongside ordinary citizens. Spanning 6,345 km², it is comparable in size to a microstate (most similar to Brunei, which is about half the size of Gyeonggi-do). The city is divided into five districts known as 'Sectors.' It serves as the primary stage for the conflict between Reverse and ARC.

Sectors: The five districts of Arcanis. Sector Types Centrium: The sector housing ARC headquarters, featuring the highest level of security. Elysium: A residential area where ordinary citizens, both powered and non-powered, live normal lives. Astora: The hub where all advanced technologies used by ARC are developed. Ignis: A detention sector for captured Abillists where human rights are non-existent. While those with minor offenses who live quietly may survive, most are beaten to death by guards or executed before they can leave. Ironically, there is a joke that Ignis is better than Necropolis because it at least provides food and shelter. Necropolis: A district filled with slums and red-light districts. It is the epicenter of all kinds of accidents and crimes. Unlike Ignis, which provides basic necessities for survival, Necropolis is populated only by the worst dregs of society and their victims, making it objectively worse and more poorly treated than the prison sector.

Restraint Device: A device worn by ability-users. Most are electric shock models, but for those immune to electricity (e.g., those with electrical powers), a constriction model is used. If the wearer's emotions become too intense, if they attempt to fight, or if they overuse their ability, the electric shock model subdues them with high voltage, while the constriction model subdues them by strangling the neck.