Ritsuka and Yuiko's teacher. She is very naive and innocent, and painfully aware of these characteristics. At twenty-three years old, she is teased and ridiculed for retaining her ears (and therefore her virginity) to such an age. She is visibly embarrassed, but as the story progresses, she gains confidence and pride over making her own choices.

Hitomi is greatly troubled by Ritsuka's mother and the injuries he sustains from her, and greatly desires to involve herself in the situation to make a change, despite her fears and her colleagues' dissent.

Her very caring and naive nature clashes spectacularly when confronted with Soubi. He brusquely rejects her and says he doesn't care for older women, despite the fact she never made a romantic move towards him and no more than three years older than him. Despite his cold treatment, Hitomi seems to have had some feelings for Soubi, due to the fact in volume 2 of the manga (episode 8 of the anime), she burst into tears and brooded over him. His brash actions are mysterious, but understood a bit more when you consider his undiscerning hatred towards teachers as a result of his experiences with Ritsu Minami.

Although he has rejected her, it can be noted that Soubi enjoys tormenting her to some degree. In their first meeting, he takes pleasure in confronting her uneasily face-to-face. In volume 2 of the manga (episode 6 of the anime), he holds her closely when she faints. This is notable because there are only two characters he physically interacts with in the entire series: one being Hitomi and the other Ritsuka.

Reasons for this awkward behavior towards Hitomi may be stemmed from jealousy. It is interesting to note that Soubi refers to Hitomi as 'childish', despite her being three years older than he is. Yet he still respectfully calls her "Shinonome-sensei." The only way he degrades her is by her sexuality, possibly because Hitomi has remained a virgin while he may have lost his ‘ears’ at a much earlier age, perhaps unwillingly. In volume 2 of the manga and episode 6 of the anime, Soubi also 'saves' Hitomi from the male Zeroes, Youji and Natsuo. They threatened to get rid of her ears, despite the Zeroes being very young themselves, and she protested immensely. Although she is grateful for Soubi's protection, it only embarrasses her more. In comparison with his extreme dislike of his own teacher figure, Ritsu, Soubi still manages to treat Hitomi as a subordinate, constantly belittling her. Ultimately, their relationship highlights traditional sexual tension, complementing the major same sex pairings and adding interest and variety to the story.

(Source: Wikipedia)