In a 'naruto x gaia academy fanfiction', Naruto is the central figure. There might also be a teacher at Gaia Academy who takes Naruto under his or her wing. This teacher could be an expert in a subject that Naruto has no knowledge of, like advanced magic (if there is magic in the Gaia Academy setting). Additionally, there could be a group of Naruto's classmates who form a sort of 'Ninja Fan Club' at the academy, with each member having their own distinct personality and role in the story.
Obviously Naruto would be one of the main characters. He would be the one bringing his ninja world charm and skills to Gaia Academy. Another could be a student at Gaia Academy who befriends Naruto early on, like a smart girl who helps him understand the academy's rules and curriculum.
Naruto is a must - be main character. Then there could be the dean of Gaia Academy. The dean could initially be skeptical of Naruto but later come to respect his abilities. And also, a rival character, perhaps a student who is used to being the best at everything in the academy and sees Naruto as a threat to his status.
One possible plot could be Naruto being transferred to Gaia Academy. He might struggle to adapt to the new academic environment which is very different from his ninja training. He could make new friends and enemies among the students. Maybe he uses his ninja skills in a school sports event, like a track and field competition, surprising everyone.
Naruto himself is usually very popular as he is the main character from the Naruto series. Fans like to write about how he would interact with the new environment of Gaia.
Obviously, Naruto and Sakura are the main characters. Naruto, with his determination and unique skills, and Sakura, with her intelligence and growing strength in the academy setting.
Well, in addition to Naruto, Gaia herself could be considered a main character in a sense, even if she might not be a physical presence all the time. If the fanfiction delves into Naruto's heritage, there could be other characters related to Gaia's past or other 'sons' or 'daughters' of Gaia in the Naruto world. And of course, Naruto's friends like Sakura would also be important. Her reaction to Naruto's new identity could range from shock to being supportive, and she might be involved in Naruto's new adventures related to his connection to Gaia.
Naruto is a given in this fanfiction. In Kumogakure, Mabui could be part of the harem. She is intelligent and in charge of a lot of important operations in the village. Her relationship with Naruto could start from her helping him with some village - related tasks. Another potential character is Omoi. Although he is male, his interactions with Naruto could lead to the female characters around him taking more of an interest in Naruto, thus contributing to the harem idea.
Sakura could be a main character. She might be suspicious of the clone at first, thinking it could be a threat to Naruto. But as the story progresses, she could come to understand the clone's situation and even help in its development.
A new, original character could be the main character in a Naruto chains fanfiction. This character could be from a small, unknown ninja village and possess a unique ability to control chains made of some special material. They could come to the Hidden Leaf Village and get involved in the events there, interacting with the well - known Naruto characters.
Iruka sensei could be a significant character. He has a big heart and might feel sympathetic towards the banished OC. He could try to find a way to bring the OC back to the village, or at least offer some moral support. And then there's Shikamaru. His intelligence could be useful in uncovering the mystery behind the OC's banishment or in strategizing to protect the OC from those who want to harm them.
Obviously Naruto would be one of the main characters. Since it's set in an academy, his classmates like Sasuke and Sakura would likely also be important characters. The academy teachers, such as Iruka - sensei, would probably play significant roles as well.
It's hard to say exactly as it's fanfiction, but it could include Naruto - like characters with enhanced, god - like powers. Maybe some new characters created specifically for this fanfic who are leaders or star students in the godlike academy.