Nakazawa Shoutarou is a violinist who appears in the fifth and sixth episodes of Seraphim Call. He sends a love letter to one of the Murasame sisters, but the intended recipient's first name is obscured by a cigarette burn on the envelope, creating uncertainty and tension between the twins Shion and Sakura. Sakura mentions that she assumes him to be very handsome, suggesting an attractive appearance. His motivation is to convey romantic feelings, though the damaged letter prevents a straightforward delivery. His role in the story is that of a catalyst, sparking the central conflict of the twin-focused episodes. His key relationship is with the Murasame sisters, specifically through the letter. No further background, development, or notable abilities beyond being a violinist are depicted in the series.