Obviously, Natsu would be one of the main characters. He's the 'badass' in the title. His fiery personality and powerful magic are likely to be central to the story.
Gray could also be a main character. His ice - making magic contrasts with Natsu's fire magic. Their friendly rivalry might continue in the academy, adding an interesting dynamic to the story as they compete in classes or in magical challenges.
There might be characters like Lucy. In the Fairy Tail universe, she's often by Natsu's side. In the academy setting, she could be studying magic alongside Natsu and getting into adventures with him.
Natsu is surely one of the main characters as the title implies. There might also be other Fairy Tail characters like Lucy, Gray, and Erza. They could be Natsu's friends or classmates in this high school fanfiction.
Most likely Natsu would be one of the main characters. And probably Lucy, Gray, and Erza from Fairy Tail could also be main characters as they are often associated with Natsu in the original Fairy Tail series.
Lucy is also quite popular. She has a unique magic ability and her character growth throughout the fanfictions is interesting. She might start off as a bit of an outsider but gradually becomes an integral part of the group at the academy.
One interesting plot point could be Natsu getting into intense battles within the academy. Maybe he has to face a new kind of dark magic user that challenges his skills in ways he hasn't experienced before.
There are several important supporting characters. Levy is one. Her knowledge of books and magic could assist Natsu in his rule, especially when it comes to understanding the history and secrets of the academy. Cana could be important too. With her card magic, she might be involved in predicting events or providing strategic advice. And Loke, as a powerful celestial spirit, could be a valuable ally for Natsu when facing tough challenges within the academy.
It could be a group of jealous students who don't like Natsu and Lucy being in charge. They might try to undermine their leadership by causing trouble during important events at the academy.
Seilah is also a main character in this context. She has her own set of powers and a rather complex personality in the Fairy Tail universe, which can be further explored in fanfiction.
Natsu could be a main character. He could be the hot - headed but kind - hearted student who always gets into trouble but also manages to save the day with his powerful fire magic. His loyalty to his friends would be a key aspect in the fanfiction.
In 'natsu rule of the fairy tail academy fanfiction', a possible storyline is Natsu's attempts to bring a new sense of unity to the academy. He may use his unique powers and charm to convince students from different backgrounds and with different abilities to work together. Also, there could be a plotline about him uncovering some secrets within the academy that are endangering the students.
Lucy could be a main character. She was always close to Natsu in the original Fairy Tail. So when Natsu returns as an 'ex' and meets the guild again, she would likely play a big role in how he is received and in the development of the story.