Full Metal Daemon Muramasa (2009)

Original title: Soukou Akki Muramasa

This is not a story of heroes. Since time immemorial, warriors called musha have ruled the battlefield, granted supernatural power by their enchanted suits of armor - tsurugi. Minato Kageaki is one such musha, driven by duty to don his crimson armor and challenge the greatest evils of an age. But though madmen and tyrants fall to his blade, never will he claim that his battle is right. For the tsurugi he wields is cursed Muramasa, which five centuries ago brought ruin to the land, and innocent blood is the price it demands in exchange for its terrible might. "Where there are demons, I slay them. Where there are saints, I slay them." These words are an oath, the unbreakable Law binding him to his armor. But they also tell the story of his past, and of the future to come.