Love
Doumoto Kaito is Lucia's love interest. Kaito is what many would consider the perfect boy - he has the looks, smarts, strength and talents. He is good at surfing and snowboarding, as seen throughout the series. Although Kaito is superficially flamboyant, he is actually a pretty docile person. He has his fair share of fears, but he hides it rather cleverly with an over-the-top ego. The series continually aludes to the fact that Kaito is anything but normal. As in, Kaito possesses some special supernatural powers and, in fact, might not be a human...
The main love story in Mermaid Melody Pichi Pichi Pitch loosely follows the original story of The Little Mermaid. Just like the heroine of the fairytale, Lucia ends up falling in love with a human. However, Lucia's story deviates quite a bit from the original source material.
When Lucia was six, she swam up to the surface of the ocean and spotted a cruise ship. She was spellbound by the fireworks display and, to express her overwhelming joy, started singing. Little did she know there was a young boy on the ship who heard her voice. Although she was taken by surprise by his presence, she quickly warmed up to him. The young boy first asked who was she and how she was able to be in the water. She then revealed to him that she is a mermaid. The boy was taken aback by this, but that did not hamper this potential relationship in any way.
While everything seemed fine and dandy for these two kids, disaster struck when the ship tilted over. The boy fell into the ocean and was very close to meeting death. However, this did not happen because Lucia managed to save the boy. She took him to dry land, but even then he was still unconscious. With that, she gave him her pearl in hopes to revive him and sang a melody from the bottom of her heart. When the boy woke up, she became relieved and returned to the ocean immediately.
Seven years later, Lucia came back to the human land to find the pearl she had given him. While she was talking a morning stroll around the area, she met a surfer by the name of Doumoto Kaito. While he looked like her childhood love, his personality was lightyears away from her lover - his flamboyant and flirty attitude even struck a sore nerve. However, one event led to another, and Lucia found out that Kaito is indeed the boy she met when she was a child as he still had her pearl with him. On top of that, Kaito still loved the mermaid which he met seven years ago.
One would think Lucia could confront him directly, but that would mean the show would just be a mere 3 episode OVA, right? And cash cows need to be epically long, meaning Lucia has a slight dilemma. If Lucia were to tell Kaito that she is the mermaid he fell in love with, she would turn into foam. Lucia did not want to turn to foam, but she did want to straighten out things. She then decides to drop hints so Kaito will realize on his own that she is his childhood love.
Through the span of many events, Lucia's attempts pay off. At first, Kaito densely thinks human Lucia and mermaid Lucia are two different people. This leads him into a lot of confusion, but he figures out that they are the same person towards the end of the first season.
Lucia and Kaito's relationship is not too groundbreaking. It conforms to the magical girl genre's ideal, "cute" relationship. Kaito tends to tease Lucia for her klutziness and pass a few quirky comments about her here and there. Although Lucia gets a bit annoyed/frustrated at his antics, she knows that he means no harm.
In PURE, Lucia and Kaito face their relationship’s greatest challenge. After the fight with Gakuto in the first season, Kaito decides to leave Japan and head to Hawaii for some good old soul-searching. While Kaito does leave Japan, an encounter from Mikeru, a new enemy of the mermaid princesses, Kaito ends up in an accident and is swept out to the Hawaiian shore. In addition, he loses his memory, mainly the memories of Lucia. A young girl named Mikaru finds him and takes him to her home. Mikaru and Kaito end up getting along relatively well; in fact, Mikaru gradually falls in love with Kaito. It can also be speculated that Kaito might have actually fallen in love with Mikaru, had he not recovered his lost memories.
Because of her older brother, Mikaru and Kaito go to Japan. It is here where Lucia finally finds Kaito. While she is happy that Kaito is alive and well, she is equally heartbroken when she sees Kaito has not only lost his memory, but seems very fond of Mikaru. She attempts to make Kaito remember his old memories, but her plans end up failing because of Mikaru’s interference/concern for Kaito.
The addition of Mikaru might have given the series closer affinity with its original source material (where a human girl saves the prince/becomes the prince’s lover). However, this is a magical girl series targeted to little girls, and Lucia is the main character. Therefore, Lucia and Kaito are eventually reunited. Only problem is, a new battle arises from it…