Relationships
Houssho Hanon - Hanon came on human land before Lucia. She recognized Lucia to be the princess of the North Pacific Ocean when she first saw her, but she doesn't give her identity to her so quickly. Instead, Hanon introduced herself as a fellow classmate and started a about Kaito. She then invited her to go window-shopping to find some "cute" things for Lucia. After Kaito's surfing contest, Hanon revealed her idenity (as a mermaid princess) and showed her dislike in the idea of a mermaid falling in love with a human. However, her dislike in Lucia's love interest dissolved when she met Tarou. After that, she suppored Lucia and Kaito's relationship. Hanon and Lucia occasional fight with each other, but they're overall good friends.
Touin Rina - Rina was mean and distant to Lucia and Hanon when she first joined her school. Lucia attempted to befriend her, even when she thought Rina kissed Kaito and is his girlfriend. To try and be good friends with Rina, Lucia made a friendship ring for Rina, Hanon, and herself. In the aftermath of Tarou's concert, Rina softened up to Lucia and became a good friend of hers.
Hippo - Hippo was sent from the North Pacific kingdom in order to be a guardian to Lucia. Hippo is completely against Lucia's love for Kaito. He constantly scolds her about it, even though Lucia ignore his words. Hippo deeply cares for Lucia's well-being, and Lucia shares the same feeling with Hippo.
Nikora - Nikora is originally a mermaid from Lucia's kingdom, though she resides on land. Lucia came to stay at her hotel when she first comes up on the human land. Lucia is like a younger sister to Nikora (and Nikora even asks Lucia to address her "big sister"). Nikora occationally scolds Lucia about her duties as a princess (or to do some chores), but deep down, she truly cares for Lucia.
Taki - Taki is a fortune teller (or clam, to be more specific) from Lucia's kingdom. She lives at the Pearl Piarre Hotel with Nikora, Lucia, and Hanon. Lucia goes to Taki for advice/fortune telling. Taki's fortunes tend to be inaccurate, and her fortunes only call for trouble. Lucia and Taki aren't very close, but they get along pretty well with each other.