Obviously, the Little Mermaid herself would be a main character. She could be joined by her friends from the sea, like a talkative seahorse or a wise old octopus who gives her advice from afar. At Ever After High, her roommates or classmates like Apple White or Raven Queen could also be important characters. They could help her adjust to school life on land.
Another possible main character could be a mermaid from a different school of magic in the sea. This mermaid could be jealous of the Little Mermaid's opportunity to attend Ever After High and cause trouble for her. And of course, any teachers at Ever After High who take a special interest in the Little Mermaid, like a magic teacher who helps her control her water - based powers in a different environment, could also be main characters.
The sea witch, or a version of her, could be a main character too. Maybe she has a change of heart and tries to help the Little Mermaid in her new adventures at Ever After High. Also, the Little Mermaid's family members from the sea, such as her father the sea king, could play significant roles. They might be worried about her and try to influence her decisions regarding her life at the school. Additionally, any love interests she might have at Ever After High or in the sea could be main characters as well.
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.
She might find herself in a situation where she has to choose between her life in the sea and her new life at Ever After High. For example, there could be a crisis in the underwater kingdom that requires her presence, but she also has important exams or events at the school. Also, she could start a club at Ever After High for all the students who are interested in the underwater world, and they could plan a trip to the sea together.
Obviously, Lily is one of the main characters. She's the mermaid around which the story revolves.
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.
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.
Well, Athena herself is of course a main character. She is often depicted as a strong - willed and curious mermaid. There might also be her friends in the underwater world, like other mermaids or sea creatures such as a wise old octopus who gives her advice.
Melody, a mermaid, is one of the main characters. She is probably the central focus, with her own dreams, desires, and challenges. Alex is also a main character. He might be a friend or a love interest to Melody. He could be from a different part of the ocean or have a special connection to the surface world. Together, they form the core of the story in the fanfiction, and their interactions drive the plot forward.
The main characters are often Elsa and Ariel. Elsa has her ice powers which create an interesting contrast with Ariel's life in the sea. They are both strong female characters with different abilities and backgrounds, so it's exciting to see them interact in fanfiction.
Ariel is the central character, a mermaid longing for a different life on land. Prince Eric is the object of her affection. Ursula, the sea witch, is a crucial character as she creates the conflict in the story. Additionally, Ariel's father, King Triton, is also a character in the story. He rules the underwater world and at first opposes Ariel's fascination with the human world. Ariel's friends, like Flounder and Sebastian, add humor and support to the story.
In the Little Mermaid story, Ariel is a central figure. She has a beautiful voice and a longing for the human world. Prince Eric is a charming prince from the human realm. Ursula is a menacing character. She makes a deal with Ariel. King Triton, as Ariel's father, has the power over the underwater domain. Flounder, Ariel's fish friend, and Sebastian, the crab, also play significant roles in the story.