For a 'Little Mermaid Naruto fanfic', Naruto and Ariel are the primary ones. However, Gaara could be an interesting addition. His past of being an outcast could parallel Ariel's feeling of not fully belonging in her own world sometimes. Then we have Ursula, the sea witch from the Little Mermaid story. In this fanfic, she could be a powerful enemy who wants to use Naruto's chakra for her own evil purposes. And Hinata could be another character, her shy nature contrasting with Ariel's more adventurous spirit as they both interact with Naruto in this unique crossover.
In a 'little mermaid lemon fanfic', one of the main characters would be the little mermaid. She would be the central figure around which the story revolves. Another main character could be an old sea witch who has a connection to the lemon - related magic in the ocean. Maybe she gives the mermaid a task involving lemons in exchange for something. And a third main character could be a young human prince who loves all things lemon - flavored and is drawn to the mermaid because of her unique lemon - like charm.
Sasuke could be one of the main characters. He might be initially skeptical or even hostile towards Naruto's mermaid side, but as the story unfolds, he could come to understand and support Naruto. Another character could be Sakura. She could use her medical ninjutsu skills to help Naruto if he gets injured during his underwater adventures.
A mermaid named Nami could be one of the main characters. She might be a curious and adventurous mermaid who is the first to approach Naruto. Another could be Marina, a more reserved mermaid but with great wisdom. She could act as a sort of advisor to Naruto within the mermaid world.
I think Misty from the Pokemon world could be a main character in this fanfiction. Since she has a connection with water - type Pokemon, she could easily fit into the underwater world of The Little Mermaid. Along with her, a Psyduck would be there. Psyduck's clumsy yet powerful abilities could add an interesting element to the story. And of course, Ariel would be a main character. She could learn a lot from Misty about the Pokemon world and they could team up to protect both their worlds from any threats.
The main characters could be the mermaid herself, who is now a young woman with a passion for ocean conservation. And then there could be a male scientist who is researching the effects of climate change on the ocean. They meet during a research expedition and form a connection.
Prince Eric could be a main character. He would be important as he is Ariel's love interest. Also, King Triton, Ariel's father, could play a significant role as he would be concerned about Ursula's return and want to protect his daughter and the kingdom.
Maybe a new character, a powerful sea witch who has been influenced by the power - hungry ways of some of Naruto's villains. She wants to rule both the underwater world and the land world above. She would use her magic to create chaos and try to stop Naruto and Ariel from uniting their forces.
Ariel is definitely one of the most popular characters. After all, she is the main character in the original story and in the fanfic as well. Writers often focus on her journey and her growth.
Obviously, Ariel would be one of the main characters. She'd be the mermaid trying to navigate high school life. Eric could also be there as the love interest. Maybe Flounder could be her sidekick, a fish - out - of - water (literally) in the high school, always getting into comical situations. And Ursula could be the school bully or the antagonist who tries to make Ariel's life miserable.
The main characters are Ariel, a mermaid princess who is curious about the human world. Then there is Prince Eric, the human prince Ariel falls in love with. Ursula, the evil sea witch who makes a deal with Ariel. And King Triton, Ariel's father who rules the underwater kingdom.