Ruka-chan was a fiesty teenage-looking demon girl that was actually over 1000 years old. Her task was to rid the world of demons and monsters that were causing more trouble than she was. Ruka's boss Enma, the Buddhist deity charged with judging the souls of the dead - an Asian St. Peter, as it were - is represented as a giant red oni in a business suit and jokingly referred to by Ruka as "Elvis". One night his body was stolen by a handsome boy known only as, well, "Body" to be used for nefarious purposes along with his army of monsters. Left with only his head, Enma scolds and demands Ruka to get his body back or else he'll gladly take hers as a replacement.