After Musashi rescues Michiru Saruwatari from a demon, his friend Kojirou Kanemaki discovers that his father was a member of the Uesugi clan. Determined to learn more about his own past, Kojirou—alongside his Kanemaki clansmen—decides to participate in Uesugi's punitive expedition against the demon lord of Awajima Island: Yamata no Orochi, an eight-headed dragon that threatens to engulf the entire region. However, upon joining Uesugi's military alliance, Musashi faces the harsh reality of fighting against powerful demons. Humiliated by his lack of power and inability to work in groups, he has to learn how to cooperate with his newfound allies. Meanwhile, the Obsidian Eight—a group pursuing the Obsidian Goddess that dwells within Musashi's body—resumes its hunt for Musashi, and plans to thwart the ongoing island operation. As the situation grows chaotic, Musashi and his friends must foil the machinations of the various factions conspiring to seize the Obsidian Goddess. The ferocious battle of Awaji Island begins now! With the appearance of the all-powerful Kishin, the land of Hinomoto is now dominated by oni, instead of humans. Musashi and Kanemaki Kojiro set out from their hometown swearing the form the strongest Bushi band of all time, and after encountering Hattori Tsugumi on their trip, the three of them found the Kanemaki Bushi. After obtaining the only weapons that can slay oni, Kitetsu Blades, they have taken the first big step towards their dream. In Harima, Musashis group will encounter the massive band of Uesugui Bushi, and their leader Uesugi Tatsuomi. They have gathered to slay the giant Kishin that threatens to consume the Awaji island: Yamata no Orochi, the Artillery Wyrm. Joining them are Takeda Naotora and the Takeda Bushi, along with several Bushi the same age as Musashi like Shimazu Akihiro and Amako Katsumi. Theres also the slightly sheltered, shy princess, Saruwatari Michiru. As different agendas swirl and interact, Musashi and his friends join the Kishin hunt. Yamata no Orochi is an unstoppable demon god thats never been scratched before. And so, the fiercest battle of all begins...