Prince Nalu is a supporting character in Barbie: Fairytopia series. He is prince of Mermaidia.
When Elina, Hue, and Bibble were travelling to the Wildering Wood, the were stopped by a group of Laverna's firebirds. Hue flew low so he could evade them, but he disturbed Nalu because he flew into a mermaid cove, Crystal Cove. Nalu was angry with Hue, but calmed down to speak to Elina.
When Hue thought that the firebirds would not come into Crystal Cove, as well as they hate water, but he was mistaken. Nalu gave Elina, Hue and Bibble some magic seaweed to eat that allowed them to breathe underwater. Nalu guided the trio toward to Wildering Wood, and as they parted ways, Nalu told Elina he hoped to see her again. Nalu was not seen again in the movie after that moment, but Elina and her friends managed to defeat Laverna, and Elina got awarded wings.
Elina found out soon after she conquered Laverna that Nalu had would been kidnapped by Laverna's fungi. Nalu was being kept at the Crystal Cove, and was to be forced to lead Laverna and her fungi to the Immunity Berry; The Immunity Berry would allow anyone who ate it to become immune to all magic, and that was exactly what Laverna wanted. Nalu reluctantly agreed, as Laverna had threatened to destroy Mermaidia with poison. When Nalu had already left with Laverna, Elina arrived with Bibble. Even though she couldn't find Nalu, she met a stubborn mermaid named Nori who is a friend of Nalu's.
Nori and Nalu had planned to meet at the Crystal Cove, but Nori hadn't known Nalu had been kidnapped. Elina is used magical seaweed to breathe underwater, and she and Nori went to search for Nalu. Nalu had sidetracked the fungi and led them astray to the Carousel of Confusion, where people forget what they're doing. Nalu confused them for as long as he could. Elina and Nori got to Mermaidia and found an oracle named Delphine so they could ask for help. Delphine told them to travel to the bottom of the Depths of Despair to find the Mirror of the Mist, which would lead them to Nalu.
Delphine was gave Elina a pearl necklace which would allow her to trade her wings for a tail; She needed a tail or she could not reach the Mirror of the Mist. If she stayed underwater for too long, she would stay a mermaid forever. Elina and Nori reached the Depths of Despair, but Nori got trapped by a sea plant. Elina used the necklace so she could swim as a mermaid and save Nori. They got to the Mirror of the Mist, and it made a bubble to lead them to Nalu. Nori and Elina followed the bubble and they locate magic fruits that can reveal the true self of whoever eats them. Nori and Elina went to the surface and found Nalu being guarded by fungi.
Bibble distracted the fungi by using a berry to sing opera, allowing Elina and Nori to free Nalu. He informed them that Fungus Maximus, the fungi leader, had found the cave where the Immunity Berry grows. Nalu, Nori and Elina fought the fungi and got the berry that the Fungus Maximus had picked. Nori and Elina secretly swapped the berry with a fake one, and had the real berry. However, Elina had remained in the water for too long, and was stuck being a mermaid forever. When Nori told Elina to eat the berry that would reveal her true self, and Elina was transformed back into a fairy, with wings.
With Laverna's plan ruined, Nalu saved and Elina a fairy again, Nalu says that everything ended perfectly. He held hands with Nori, which confused her because she thought Nalu loved Elina. Elina told Nori that she and Nalu are just friends, and that he was in love with Nori. While Nori was embarassed to reveal it, but she did let him know she returned his feelings.
- In Barbie: Fairytopia, Nalu was credited as "Prince Kai." The name Kai is also water-related, meaning "ocean" or "ocean wave" in Japanese.
Barbie in the 12 Dancing Princesses
Barbie as the Island Princess
Barbie: Dreamhouse Adventures