Namazu

''This is for the character. For the story, see Namazu or the Big Fish Story''.

Namazu is a giant catfish which lives under Japan in Usagi's world. Any time it moves, an earthquake is felt on the surface. Thunder god Kashima-no-Okami battled Namazu and subdued it with a giant rock called Kanameishi. A bit of the rock is exposed above the surface, and any bit of the rock that is chipped away, gives Namazu more leeway to move. Kashima himself struck Kanameishi with a stray bolt of lightning during a quarrel of the gods and broke off a piece, which Kakera tasks the and Usagi with accompanying him to mend. Although they run into Jei and his brigands, Kakera is successful in restoring the rock, which sinks lower to jam Namazu even further in place.

Trivia

 * Namazu (鯰) is simply a Japanese word for catfish, but there is specifically a giant catfish in Japanese mythology called that, which was said to be responsible for earthquakes until trapped under a giant rock by Takemikazuchi/Kashima-no-Kami.