A thoughtful and caring Melusine who serves as the Fortress of Meropide (Fontaine’s underwater prison)’s Head nurse. Being a Melusine, she cannot “feel” human emotion and must study them intellectually, making her rather good at reading others. She likes “playing dumb” as she likes the feeling of being trusted, but never uses her manipulative skill with malice. Sigewinne has a fondness for making healthy drinks for her patients and friends, but they always look gross.