The mighty creatures known as "Kamikui" are attacking ancient Japan, and it is up to the "Oni" and his band of eight beautiful female warriors to stop them. These females each have their own set of skills, powers, and personalities. They join forces with the Oni, Jin, to put an end to the darkness that is engulfing Japan. Onigiri follows Jin and his merry band of misfits as they deepen their relationships and repel the demonic invasion.