Sakura Uchikubo (Luna Park) - Sakura is the daughter of the head of Ushikubo Medical Manufacturing Group and is Kei's first marriage meeting (or omiai) partner to appear in the series. While she does not consider Kei her type, describing him as a "dark lord" rather than a "prince", she considers him a possible marriage partner because his abilities would be advantageous to her family's business. Sakura hates dishonest people with a passion, and her family's motto is centered around honesty and punishing/loathing dishonest people. Hikari's straightforward and honest nature allows the girls to become friends. She attends the same school Yahiro does and sometimes plans stuff out with him (whether the plans be good or evil). Sakura falls in love with Jun at first sight, as he fit her ideal of someone who was a "prince", and accepts his split personality. She begins to date Jun soon after; however, because of her forceful personality, she is uncertain if Jun reciprocates her feelings until he admits to her that he does. 

Yahiro Saiga (Lee Taemin) - Yahiro attends Kokusen Academy, another high school, and is the heir to the Saiga Financial Group, a group that is even higher in status than the Takishima group. Because Yahiro's attitude towards others often upset them, he had very few friends as a child aside from Akira and Kei; his relationships with both of them eventually became strained and distant from his overprotective attitude toward Akira. As a result, Yahiro chose not to become friends with anyone until he met Sakura; at first, he had rejected her offer to become friends with her, but complied after they went through a lot of trouble to save the rabbit they were trying to bring back to its home in the mountains.

Yahiro has harboured a crush on Akira since childhood and is very protective of her, willing to use whatever means necessary to protect her, even if she hates him for it. It is this protective nature that made him drive away Akira's only friend, Sayo, after he overheard her saying how she never liked Akira and was only her friend because Akira was rich and she enjoyed all the privileges and status that came with the friendship. Akira had believed that Yahiro had been jealous of her relationship with the "poor" kid she was playing with and never forgave Yahiro for ending her friendship with Sayo. He never told Akira the truth and has no intention of telling her. His hatred of "poor" people comes largely from this incident, which made him believe the poor exploit the rich. He eventually gives up his feelings for Akira, telling Tadashi that if he ever makes Akira cry, he will never forgive him. Because he still cares for Akira, Yahiro is initially unable to reciprocate Megumi's feelings for him, but comes to see her as an important person to him and encourages her to sing.

Finn Coupe schuzzete (Amber Liu) - Finn is the prince of a small country whose true gender has been concealed from the public. She initially appears as a reluctant participant in a series of arranged marriage meetings Kei's grandfather sets up for Hikari. When Hikari flees from the meeting, Finn approves of her on the spot, since Hikari fits the exact description of Finn's ideal person: a woman with long dark hair possessing a sweet yet tough personality who wears a red dress. After helping Hikari escape, Finn follows her to Japan with the intention of proposing to her. The SA later discover that Finn's mother fits the description of the ideal person Finn wants; Hikari tells Finn that it's a wonderful thing to look up to her mother so much before adding that she and Finn can still be friends. Afterwards, Finn enrolls in Hakusenkan and tries using Ryuu to get closer to Hikari, but ends up becoming very good friends with him. However, her feminine behavior towards him confuses Ryuu until he learns her true gender. Finn's exact ranking in Hakusenkan has not been revealed, but it is known that she is in C class.

Ryuu discovers not long after meeting Finn that the prince is actually a girl; in Finn's country, the law states that the country must be ruled by a male and if the heir is a female, she will be raised as a male. Upon explaining this to Ryuu, she asks that he keeps her secret as they will be severely punished if it is revealed. Shortly after Hikari discovers Finn's secret, Finn and Hikari attempt to convince Finn's father to allow Hikari to return to Japan rather than face life imprisonment in Finn's country. The issue is resolved when it is revealed that Finn's mother is pregnant and the baby will be a boy; Finn is revealed to be a girl to everyone else and her unborn brother will become the heir to the throne. She and Ryuu also become a couple, and she starts dressing up as a girl at the conclusion of the series.