The Prohibition was established about four years before the start of the story. It is a collective agreement between all human nations of the Mortal Realms to outlaw the use of Common Magic by anyone for any reason. Individuals or groups violating its terms are to be prosecuted by the united forces of all kingdoms. The Prohibition was established because of a possible link between the practice of magic and the appearance of a terrifying human assassin who is invulnerable to magic.

The lives of many whose professions were deeply connected to sorcery were devastated. There was some protest against the solution due to its impact on every human's daily lives, but most were eventually convinced by the theory.

Because of the Prohibition, positions previously occupied by sorcerers were recently replaced by Beast-Human mercenaries, whose magical abilities do not stem from Demon spirits. This trend brought many Beast-Humans into human towns where they previously preferred to keep to their own tribes.