The villains in the Naruto universe could also play a role. Maybe the one who turned Naruto into a fox was an enemy seeking revenge or trying to gain some advantage. Orochimaru, for example, could be behind it, hoping to use Naruto's new form for his own evil experiments. And then Naruto, in his fox form, would have to fight against Orochimaru's minions to protect himself and his friends.
Obviously Naruto himself, as he is the one turning into the Nine - Tailed Fox. Sasuke would also likely be involved. He might be the one to try and reach Naruto when he is in his fox - form, either to fight him or to bring him back. Sakura too, she could use her medical ninjutsu to try and help Naruto if he gets injured during the transformation.
Obviously, Harry and Ron would be highly involved. They are Hermione's closest friends. Harry would likely be the one leading the effort to find a solution, given his heroic nature. Ron, on the other hand, would probably be more involved in the day - to - day care of baby Hermione, with his big, caring heart.
There could be new characters specific to the village where he becomes Kamikage. For example, some powerful shinobi clans within that village. Their leaders would be important as they could be Naruto's allies or opponents. Also, the previous Kamikage's advisors might still be around and play a role in guiding or challenging Naruto. Maybe an old sage - like figure who has deep knowledge of the village's secrets and helps Naruto understand and respect the village's heritage.
Obviously, Tails himself is the central character. Sonic is very likely to be involved as well, either as someone who tries to help Tails after he's hurt or as a factor in the situation that led to Tails' injury. Dr. Eggman could also be a key character, perhaps as the one who caused Tails' hurt in the first place.
Sakura could also be a character in these types of fanfictions. Since she had feelings for Sasuke for a long time, some fanfiction writers might come up with a plot where she cheats on Naruto (if they were in a relationship in the fanfic) because of unresolved feelings for Sasuke or some other factor like a misunderstanding with Naruto.
Obviously, Naruto himself is the main character in this situation. His friends like Sasuke and Sakura are very likely to be involved. They would be the ones taking care of him, trying to figure out how to turn him back to normal. Kakashi Sensei would also probably be there, guiding them and trying to keep Naruto safe.
Obviously Naruto himself is the central character as it's about his hibernation. His friends like Sasuke and Sakura are also likely to be involved. They would probably be the ones most concerned about his condition and try to figure out what happened.
Obviously Naruto himself would be the central character. Then, characters like Iruka Sensei could still be involved as he was one of the first to notice Naruto's potential in the original story. Also, Sasuke might be there as Naruto's rival. Even the Hokage, whether it's the Third Hokage at first or others later, would likely play a role in guiding or at least observing this unique Naruto.
Naruto himself could be a victim of family betrayal. His father Minato or mother Kushina might be involved in some alternate - universe plot where they turn against him for some dark reason. Sasuke's family is also a likely candidate. Itachi's actions could be re - imagined in a way where his real motives are more about betrayal of the Uchiha family rather than protecting it. And Hinata's family might be involved too, like if Neji, before his death, was made to betray the Hyuga family in some fan - created scenario.
Obviously Naruto himself. Then Sasuke would probably be involved as they have a deep connection. Sakura too, since she's part of their team. Kakashi might also play a role as Naruto's former teacher.