Tohru and Noburo are brothers of the Takagami Family. Toru has Yin in his blood and is constantly targeted by the youkai and other creatures lurking in Japan. When Tohru is targeted by one, his brother Noburo releases the fox deity Kuugen Tenko who protects Tohru from the monster. Kuugen now acts as the protector of Tohru and Noburo to keep them safe from any threats to them, while at the same time trying to adapt to the modern world.

(Source: Wikipedia)