|Voice Actor||Daisuke Kishio|
|Anime Debut||The Lonesome Princess|
Kodoku na Ōjō(孤独な王女)
Gaito (楽斗/ガクトGakuto) E o Diretor antagonista da 1 ª temporada de Mermaid Melody. ELE É O LÍDER DOS Monstros Marinhos que estavam invadindo Cada hum dos Países Fazer Princesa Sereia e obcecado com Tomando Conta do Mundo.
His two main goals were to find his twin brother, Kaito, and to capture all seven of the Mermaid Princesses. He needed Kaito because he thought that once the two were together, their powers combined were strong enough to take over the world, not knowing that it was strong enough to destroy the world instead. He needed all seven Mermaid Princesses to revive Aqua Regina, who he thought he could use to assist him in taking over the world.
Like Kaito, Gaito is part of the Panthalassa race and was one of the descendents who was given a curse fate, Gaito possessing the power of darkness. Because Aqua Regina lacked the power to break the curse, she had to separate them, causing Gaito to become very lonely. He lived at the very bottom of the sea and was only accompanied by his sea creatures, whom later became the Dark Lovers with his dark magic. He later came across Sara, whom he believe was going through the same sort of loneliness that he was going through, causing him to fall in love with her.
Gaito has a soft spot for Sara, the Orange Mermaid Princess. In the last episode when Sara joins the other mermaid princesses, Gaito was hurt and so had hardened his heart against her believing that he was betrayed. When Sara and the other mermaids confront Gaito in his room he starts releasing lightning. Sara tries talking to Gaito but he does not want to listen. Gaito electrifies Sara, causing Sara to drop on the floor. The other mermaids began singing leaving Gaito to weaken and lose his powers. As Gaito becomes powerless and his castle begins to sink, everyone starts to escape but Sara stops. She explains why she wants to stay with Gaito, and the two die together.Gaito has spikey gray hair and pink eyes. He wears lightning earrings with a loosely attached black robe with black pants and pointy shoes. He has a dark red necklace and is usually seen holding a rose, wine, or his staff.
When he was disguising himself as his twin brother in an episode, the only difference was Gaito's eyes, showing evil and hardness. He is apparently physically strong despite that he hardly does any sort of fighting throughout the series.
- His real name is Gakuto, which means educated person.
- His former love interest was maria, but his current love interest is sara.