Eddy Kitsis says that Ariel is one of their favorite characters and they have ideas for her but they are unsure as to whether or not they will introduce her because they want to get it right. They want to make sure that they can bring her story line justice if they bring her in. They don’t feel that they completely did so with Ruby who turned out to be the wolf in season one but then lost her story in season two.
Adam Horowitz, the other creator of the show warns that if they do bring Ariel in, she won’t be the fun fairytale character that everyone knows from Disney. They will put the “Once Upon a Time” spin on her so that they can tell their own version of the story. Hopefully, Ariel won’t become a villain or have some really twisted story that makes her completely unrecognizable
The rest of the story
http://www.examiner.com/article/once-upon-a-time-season-3-spoilers-will-fans-see-the-little-mermaid
Note: Fairytale character she must be from FL not NL then right ❓