Gama and the others storm Unabara castle only to find their path immediately blocked by a monstrous giant lurking beneath the ground-Arimaru! Gama and his allies struggle to ward off Arimaru's underground assault until Shinnojo puts his life on the line and successfully brings her to the surface! However, it's Zenmaru who steps in to fight Arimaru in Shinnojo's place. Determined to evolve as a warrior, he draws his Sadanaga against a deadly foe!