Kayako Yuzuki is a young woman who works for City Hall.Her (possibly twin) sister is Kayoko Yuzuki.
She has red glasses, green hair and green eyes. Unlike her sister, she wears more casual clothing like a sweater and a skirt.
She's kind and patient, but has an aloof and childish side to her that is showcased on her 'date' with Yuuya. She often tries to be mature, but it can fail miserably.
She was an old childhood friend of Yuuya's from when they were younger, but they lost contact until they met again because of Izaemon. She is seen as a big sister figure to Yuuya, who even calls her 'Kaya-nee'.
Like Kanna, Sayuri and Haruka, Kayako knew Yuuya when they were kids. She typically calls Yuuya 'Yuu-bou'. It's unclear if she officially likes Yuuya or was just teasing him.