A rather shy and quiet girl most of the time, Hikari tends to not be very outspoken and it usually takes a lot for her to say what is really on her mind. Much like Nagisa Aoi, Hikari is also a transfer student, arriving at Spica in the second year. In that same year, she joined the St. Spica Choir (also known as the Saintly Chorus) with her best friend and roommate Yaya Nanto. Later, she starts to develop a crush on Amane Ohtori, and they begin showing intense feelings of attraction for one another.
She tends to be a physically weak girl who is fairly easy to be taken advantage of, much to her dismay. Unpleasant experiences related to her vulnerability seem to have inspired some fear of unexpected physical proximity in her. She does, however, have friends that look out for her well being. Hikari also seems to be very religious and can be seen praying within the church or at the Spica fountain with a statue depicting the Virgin Mary on the school grounds.