Humans lived together with spirit youkai in ancient times. But because demon youkai decided to control humans, the two kinds of youkai fought in a violent dispute. At that time, a swordsman appeared who taught both sides a way to battle without killing each other. From then on, until the day when the winning side removes a seal from the losing side, they possess a great power in the human world. And now the bamboo flowers are in full bloom, so the day to remove the seal has come.  Now the power lies with the winning demon youkai who proclaim they will maintain eternal control over humans in the next battle. But victory or defeat lies with the supreme commander who must be a human child this time. The head of the spirit youkai Nurarihyon forsees that and commands that Maya search for an appropriate human child to be the supreme commander.