Secretary to Rei's father
Takashi Hino, Rei Hino, his fiancée
Kaidou was the secretary to Rei Hino's father and while she disliked her father, she was fond of Kaidou and began to crush on him. Kaidou, Rei and her father would spend her birthdays together; every year her father would give her the gifts of a white dress and a bouquet of Casablanca lilies. Rei knew, thanks to subtle hints dropped by Kaidou, these were always picked out by him and not her father.
Rei's father decided he wanted Kaidou to take over his position when he retired, and insisted that Kaidou be married in order to maintain a good impression. Rei saw him being affectionate with another woman, and after she confronted him about it Kaidou announced his engagement to the woman. The woman was the daughter of another high-class politician from his circle of friends and co-workers, Rei's father had picked her out, knowing together they would be a perfect couple.
Rei was devastated by the news because she felt that Kaidou understood her views on marriage, relationships, and love. Kaidou's feelings on Rei were never firmly stated either way; he was shown to care for her, but he also seemed to be happy with his fiancée. In fact, when Kaidou told Rei that his marriage was only a political move decided by her father, she called him a liar and said that if Kaidou truly wanted to use marriage as a way to gather power, he would have married Rei herself. The two then shared a kiss.