Kaito, the son of a pair of musicians, is an avid surfer, as well as Lucia's love interest. Though he is popular with girls, he is secretly in love with a beautiful mermaid who saved him from a shipwreck seven years ago, and has yet to realize that this mermaid is Lucia.

Spoiler

Later in the story, it is discovered that beneath Kaito's human exterior lie some distinctively un-human qualities.