This is not a story of heroes. Minato Kageaki is a musha — a warrior bound to an enchanted suit of armor called a tsurugi — who fights the greatest evils of his age. His tsurugi is the cursed Muramasa, a blade responsible for catastrophic destruction five centuries ago. It demands innocent blood as the price of its terrible power. Kageaki slays demons and saints alike, bound by an unbreakable Law and haunted by what that oath has already cost — and what it will yet demand of him.