|Name: Kaito Domoto (堂本 海斗 Dōmoto Kaito)|
|Birthday: November 21|
|Birthplace: Panthalassa Kingdom|
|Species/Race: Panthalassa Clan|
|Hair Color: Ginger|
|Eye Color: Brown|
|Height: 172 cm (5'8")
Blood Type : A
|Star Sign: Scorpio|
|Profession: Surfer, Student|
|Favorite Subject: Physical Education, Mathematics|
|Least Favorite Subject: Social Studies|
|Favorite Color: Blue|
|Favorite Food: Stew|
|Favorite Type of Girls: Low Maintenance Girls|
|Family: Gaito (brother), Makoto (cousin)||Best Friend: Unknown|
|Love Interest: Lucia Nanami|
|Voice Actor: Daisuke Kishio|
|Position in the Series: Main Character|
Kaito (堂本 海斗 Dōmoto Kaito) is in love with Lucia and is the twin brother of Gaito. He is an orphan; his parents died when their ship capsized during a storm (caused by Sara when her pearl was out of control). However, as he discovered later, those were not his real parents; he is a child of the Panthalassa.
He is the twin brother of Gaito. This is because the Phanthalessa imbued their descendant's power into the two twin boys which, when joined, allows power to destroy the world. This is why Aqua Regina separated Gaito and Kaito. He washed up to shore wrapped in seaweed after a storm and a couple who were musicians found him. From there they raised him. While Kaito and his parents were on a cruise Sara was angered by Taro abandoning her and she created a big wave that shipwrecked the cruise ship and killed both of Kaito's parents. Fortunately, Lucia saved Kaito and brought him back to shore. He continued to be unconscious so Lucia used her pearl to save him. And he wound up raising himself.
Kaito is very interested in surfing since he was still a child, and is a very easygoing person. He is shown to be popular with girls and can be quite flirtatious, even perverted to an extent, as he comments on Lucia's outfit that her clothes are cute, but he prefers "more racey outfits."
He is completely oblivious to the fact that Lucia is the mermaid that saved him as a child. Despite this, he had several times where he questioned if Lucia could be that mermaid and compared her human and mermaid forms throughout the series.
His hair is orange-brown a little red and spiky and he has brown eyes. As pointed out, he resembles his brother Gaito. He wears a variety of different clothes on land such as a white jacket and black turtle neck or a red jacket and a white shirt. While surfing he wears a red, black, and slightly yellow wet suit. In water he wears a blue, red, and yellow outfit with a whiteish cape. His school uniform looks like any other male uniform of his school with a white button down shirt and blue pants.
See: Kaito Domoto/Gallery
- Chinese: Lin Guzhen
- English: Blake Shepard
- French: Emmanuel Deknoinck.
- Greek: Yiorwos Mataragas (Γιώργος Ματαράγκας)
- Italian: Simone D'Andrea
- Japanese: Daisuke Kishio
- Korean: Byeon heyon woo
- Portuguese: Sérgio Calvinho
- Serbian: Milan Antonić (Милан Антонић)
- Spanish: Alvaro Navarro
- Hebrew: Gilan Shahaf