Sansei Muramasa is a prominent character in the visual novel 'Fullmetal Daemon Muramasa'. She is a sentient suit of armor known as a Muramasa, which is a mythical and powerful weapon in the series. Sansei is a complex character, embodying both the traits of a ruthless warrior and a compassionate being. She forms a deep bond with the protagonist, Minato Kageaki, as they navigate moral dilemmas and the consequences of wielding such destructive power. Her role is pivotal, often challenging the protagonist's ideals and pushing the narrative towards its philosophical depths.