Oni (鬼) are creatures from Japanese folklore, similar to Western demons such as ogres and trolls, These nebulous beings could also take on a variety of forms to deceive (and often devour) humans.

Heaven and Earth are described like "KenKon", in Japanese "Ken" (天) indicate the Heaven and "Kon" (地) the Earth. Heaven is represented like a circle and Earth like a square; symbolizing the immensity of Heaven and Earth. Heaven refer to soft and Earth to hard.