Naruto for sure. Then there could be some original characters created just for this fanfic. For example, a spirit - like character who becomes Naruto's guide in the academy. Another main character could be a rival student from a different village who has his own set of skills in spirit detection. And Hinata might also be part of the story, her Byakugan ability could be useful in detecting spirits in a different way.
Well, it could be about Naruto enrolling in a spirit detective academy. Maybe he discovers new powers related to detecting spirits there. He might meet new friends and foes, and they all have to solve mysteries involving spirits together.
Obviously, Naruto would be one of the main characters. He brings his ninja skills, his determination, and his go - get - it attitude. Rias Gremory could also be a main character. She is a powerful devil in Kuoh Academy and her leadership skills and her relationship with Naruto could be a central part of the story. Issei Hyoudou could also play a major role as he is a key figure in the Kuoh Academy setting and his interactions with Naruto would be interesting.
In this fanfiction, Naruto is the central figure. Hinata could be another main character. She has always had a crush on Naruto, and in the 'Handsome Academy', she could be shyly trying to get closer to him while also improving her own charm. Kakashi could be a teacher at the academy. He has his own unique charm and could be guiding the students in the ways of the academy, which includes both academic and 'handsome - related' teachings.
Rose Hathaway is a main character. She's a strong and brave dhampir (half - vampire, half - human) who is training to be a guardian. Lissa Dragomir, a Moroi (a peaceful vampire), is also important. She has a special bond with Rose.
Well, clearly Naruto and Anko would be the main characters. Naruto is the protagonist of the original Naruto series, known for his determination and his powerful jutsu. Anko is a strong kunoichi with her own set of skills and a bit of a wild side. In a fanfic focused on them and a spirit theme, they would be at the center of the story.
Obviously Naruto would be the main character as it's a Naruto - related fanfic. But other characters like Sasuke could also be important. Sasuke might be initially skeptical of Naruto's new spirit bomb - like ability or could even be jealous. Sakura could play a role in helping Naruto master this new power, maybe by using her medical ninjutsu to keep Naruto in top shape during his training.
Most likely Naruto himself would be a main character. He's the protagonist of the original series, so it's reasonable to assume he'd play a major role in this fanfic too. Sasuke might also be there as he's an important part of Naruto's story.
Obviously, Naruto and Hanabi are the main characters. Naruto, the hero of the original Naruto series, and Hanabi, an important member of the Hyuga clan.
It could be Orochimaru. Even in the academy days, he was already plotting and scheming. If Naruto time - travels back, Orochimaru might see him as a threat to his early plans and target him. Orochimaru's thirst for power and knowledge makes him a great antagonist for this scenario.
The main characters in 'ash academy fanfic' could be the students who are at the center of the story. It might be the top - performing student, or the troublemaker who causes all kinds of chaos in the academy. There could also be teachers as main characters, especially if they play a crucial role in guiding the students or if there are some mysteries surrounding them.