Musashi and Kojirou were once inseparable best friends who, at the age of 10, listened intently to Kojirou's father's stories about valiant warriors who defeated evil demons. Determined to become the strongest warriors in the world, they practiced swordfighting and made a solemn vow. However, as they grew older, Kojirou became pessimistic, and Musashi felt overwhelmed by the centuries-old rule of the demons. Despite being hailed as a prodigy with a pickaxe, Musashi felt a lingering sense of duty to fight against injustice, even as he prepared to settle into a life of manual labor. But as the injustices in his world continued to mount, Musashi knew that he couldn't ignore his call to action forever.