Nisei Muramasa is a key character in the visual novel 'Fullmetal Daemon Muramasa.' As a fullmetal daemon, she is a living weapon with the ability to manifest as a powerful suit of armor. Nisei is known for her complex personality, embodying both a fierce warrior spirit and a deep sense of introspection. Throughout the series, she serves as a formidable ally and a moral compass to the protagonist, grappling with the ethical implications of her existence and the battles she is thrust into. Her inner conflict and dynamic interactions with other characters drive much of the narrative's tension and emotional depth.