According to legend, Saiunkoku was once infested by demons who threw the country into turmoil and made the people miserable. A brave young warrior named Sō Gen gathered together the eight Enlightened Sages of Colour and drove away the demons.

Sō Gen then forged the nation of Saiunkoku and became its first emperor. After Sō Gen's death, the eight sages disappeared, but according to legend they still exist among the people. A beautiful shrine was built for the Eight Coloured Sages; it still stands within the Imperial City.

Saiunkoku had always been divided into eight distinct provinces named after colours of the rainbow. Six hundred years ago, the Emperor commanded that the ruling family of each province change their names to match the province they ruled. Commoners were forbidden to share the same family names as nobles.