Gai's right arm was forged from the demon sword Shiryuu after he lost the original while working as an apprentice to the swordsmith Amon, and he can fuse with the blade to fight. In this second part, the cursed power of Shiryuu grows stronger inside him with each passing day. Meanwhile, Shoshidai and the mysterious Gabi press on with their mission to protect humanity. The series is a supernatural action ONA.