Leofin Krímnirs (レオフィン・クリームニルス), better know by his nickname Leo (レオ), is a young boy that was a introduced as a candidate for Rotte's harem and later was given special permission to attend the women's Royal College of Ygvarland. He likes to dress in female clothing and likes to do feminine things.
Leo is a young Varhund. He has dog-like button ears at the top of his head and has light hair. He is mostly seeing wearing girl's dresses, but when first introduced he is seeing wearing a butler's uniform like Naoya. Contrary to Úrsúla and Eldór, he is shown to have a short and bushy dog tail.
Leo is a very timid boy. Insecure and slightly gloomy at the beginning due to his taste for girly stuff, he eventually gets confident and shows a bright personality once he meets and interacts with Naoya. Despite his effeminate aura, he is not gay. He gets extremely uncomfortable when Asuha drags him to the women's side of the school's onsen and eventually ends up dating Elíka.
Viscountess Krímnirs, Leo's mother, finds out that Rotte has started a harem, so she uses the situation to propose Leo as a new candidate for the harem. Judit uses this as an opportunity to put pressure on Naoya to force to act more aggressively towards Rotte, but this immediately backfires since, instead of feeling a rival, Naoya finds a good partner in Leo.
Naoya shows Leo the activities that he has to do as a harem candidate. Upon seeing Críe, Leo appears to be captivated by her appearance, something that he denies. In response Críe, forces him to dress as a maid and he appears to be uncomfortable with this. Later at night, Leo goes to check if Rotte's bed is made. There he finds Rotte's doll slightly untidy, so he brushes the doll a little bit. Rotte, who was watching while hidden, recognizes his tactful ways and acknowledges that she has no reason to fire him as she originally wanted.
When Rotte brings Leo to school, she starts ordering him to buy several foods for her, successfully meeting Rotte's expectations. Chatting with Naoya, Leo asks if Naoya isn't bothered by his presence as another harem candidate. Naoya tells Leo that he thinks that Leo will be a good influence on the princess in the same way that happened with him. As Naoya points out how radiant Rotte's smile has become, he says that he wants to see Leo smile in the same way, unexpectedly charming Leo to the point where Leo avoids changing clothes together with Naoya since he has become embarrassed at the prospect.
At night, when he is folding and putting away clothes, Leo finds an extra maid uniform. He puts it on believing that no one is watching, but, soon after, Naoya accidentally discovers him. Leo confesses to Naoya that he likes dresses and cute things since he was younger, but, three years ago, her older brother, who was supposed to become the head of the house, eloped with another man, leaving Leo to become the successor. Due to this, he was forced to become more masculine, but he was unable to suppress his tastes and only kept them hidden. That point was the first time that he had worn girl's clothing, not because he enjoyed crossdressing, but because he thought the dress was cute. Naoya comments that, in fact, Leo was showing the sincere smile that Naoya wanted to see and tells Leo that the natural version of him was better, once again inadvertently seducing Leo. While flustered by the situation, Leo is happy by Naoya's words
Encouraged by Naoya's words, Leo later decided to quit being a harem candidate in order to not interfere with Naoya's and Rotte's relationship, besides not feeling himself being suitable for Rotte. Judit comments that Leo's mother will be disappointed since she seemed to want to become a fraternal relative, but Leo tells Judit to use his disposition as the reason to fire him in order to discourage his mother from further attempts.
The following day, Enja introduces Leo as a full-fledged student of the girls' side of the school since he know has decided to no longer hide his passion and wears girl clothes and it would be more problematic to have him go to the boys building, something that surprises Naoya and Rotte.
When the onsen facilities of the school are almost finished, Enja invites Rotte and her friends to use the facilities. As Leo and Naoya start going the to men's section, Asuha holds Leo and brings him with the girls. While the girls are enjoying the water and a ruckus is started by the outrageously bold swimsuit that Míst is wearing, Leo can only avert his gaze as much as possible. When Enja arrives and all the girls decide to go nude, Leo tries to leave the onsen, but he's once again stopped by Asuha, who makes him also take off his swimsuit.
At the end of the manga, it is revealed that Leo and Elíka had secretly developed a romantic relationship and, after Rotte announced that Naoya was going to be his legal spouse, they decide to announced that they were dating on the condition of getting married, slightly disappointing Asuha, who was also gunning for Leo.