The Ôgame school tries to enter Unabara Castle. His progress is stopped by a grotesque-looking giantess moving underground: Arimaru! Arimaru's underground attacks undermine our heroes. Shinnojô sacrifices one of his feet to reach the enemy in his gallery, pushing her to surface! That's when Zenmaru takes over. Eager for martial progress, he draws Sadanaga to face this formidable opponent...