Naruto. He's known for his unorthodox fighting style. When he goes all out, he might pull out some really unexpected moves. For example, he could combine his shadow clones with a new type of Rasengan variation that Neji has never seen before.
Honestly, it could go either way. Naruto is more impulsive and likely to try something crazy on the spot. But Neji, being a strategic fighter, might also have some hidden tactics up his sleeve. In the heat of the battle in this fanfiction, both of them could be pushed to their limits and come up with unexpected maneuvers depending on how the story unfolds.
It could be Neji too. Although he has his traditional Gentle Fist and Byakugan - based tactics, in a situation where Naruto is going all out, he might be forced to deviate from his usual approach. He could use the Byakugan in a new way, like predicting Naruto's clones' movements in a more complex manner and then use a long - range Gentle Fist attack that catches Naruto off - guard.
In this fanfiction scenario, the outcome might also be a draw. Maybe they both reach a point where they realize they are evenly matched. Naruto's strength and Neji's precision could cancel each other out. They might then come to an understanding and end the fight without a clear victor, which could also lead to a new friendship or alliance between them in the context of the fanfiction.
Rock Lee might be an interesting choice. He is Neji's friend and has a strong sense of loyalty. He would be very dedicated to taking care of the baby. His physical strength could also be useful in case of any danger. And his positive attitude would be great for the baby's environment.
In such a fanfiction, Naruto might be driven by a strong motivation. Maybe Neji has said or done something that Naruto can't tolerate. Naruto, with his powerful jutsu and unwavering determination, could overpower Neji in a fierce battle. His Rasengan might be a key move to gain the upper hand.
In this fanfiction, Naruto will surely interact with his friends who might be trying to break him out or at least communicate with him from the outside. Inside the prison, he'll encounter inmates with diverse personalities. There could be a wise old prisoner who imparts some valuable wisdom to Naruto. Also, there may be a group of inmates who form a sort of gang within the prison, and Naruto has to either fight them or make peace with them depending on the situation. And of course, there could be a mysterious figure who seems to know more about Naruto's presence in the prison than he himself does, and Naruto will have to figure out this person's motives and identity.
Obviously Naruto himself. Since he is the one going to the past, he would be the central character. His younger self would also be important as he would interact with his future self.
Makarov could be a great teacher. He has a wealth of knowledge and experience in magic. He could teach advanced magic techniques and also lessons about leadership and guild values. He would be strict but also very understanding and always ready to give good advice to the students.
In this fanfiction, Dudley would surely interact with the Hogwarts professors. Professors like McGonagall would be strict with him, making sure he follows the rules. He might also cross paths with Draco Malfoy. Given Malfoy's attitude towards Muggle - borns, there could be some conflict there. And let's not forget the other students in his house. They would play a big role in his Hogwarts experience, either befriending or ostracizing him.
Sasuke would probably be one of the first to support Naruto. They have a deep bond and Sasuke respects Naruto's strength. He would see Naruto's victory over Hashirama as a sign of Naruto's growth and power.
Obviously Naruto would be one of the key characters. Since it's about his generation going back in time, he would be central to any attempts at changing the past. His knowledge and his will to protect his village would drive many of the actions.
Obviously, Naruto and Kurama are going to be main characters. Since it's about Kurama going back in time, he'll be central to the story. Naruto will also be important as Kurama's jinchuriki and the one whose life Kurama is likely to impact. Minato might also be a significant character as he was Naruto's father and had a major role in the original story. And there could be appearances from other key characters like Sasuke, as Naruto's relationship with him was a big part of the original Naruto series.