But despite of the wide selction of girls he can choose from, Kaito has already given his heart to the mermaid Lucia he met when he was little. Even under the affection of the prettiest girls he is still unmoved. However, you can tell that he does like Lucia more than the other girls, because he really cares about her a lot and she seems to be the only girl he really talks to. He even claims to see some resemblence between Lucia and the mermaid (he doesn't know that Lucia IS the mermaid)! He was confused about his feelings at first whether he likes Lucia or the mermaid, but eventually chooses the human Lucia because she understands him more than anyone else, and truly cares about him.

Judging from a few clues seen, we can conclude that Kaito may not be a regular human. First of all, he has a striking resemblence to the sea monster clan boss, and their names are even the same! and secondly, when Yuri plays her mesmerizing music in episode 4, every other humans were controlled besides Kaito. He got attacked by the humans who were going after the mermaid princesses! In addition, in episode 5 he is able to understand a dolphin. This turns out to be true, because he saves Lucia numerous time during the second half of the series, by shooting out a great beam of light from a symbol on his forehead (and screaming "LUCIAAAAAA!!!!" xD). Everytime he does that he faints and forgets what happened, and has no idea he is Aqua Regina's son until he was captured by Gaito.