Aoi Hyūga (日向 葵 Hyūga Aoi) is Natsume's cheerful younger sister, appearing mainly in the manga. Aoi tells Ruka that her brother doesn't smile often so she has to smile for him, and so she is usually seen with a cheerful smile on her face, even when shocked or surprised, much like Koko. She originally possessed a Fire Alice like her brother, but it eventually disappeared. Aoi was, at one point, referred to as "Yuki Aoi" by Persona, possibly so that Natsume could not find her as easily.