I really like 'Naruto, Sasuke and Sarutobi: A New Beginning'. In this fanfic, it starts with Sarutobi having a premonition about the future of Naruto and Sasuke. So he takes steps to guide them differently. It's an interesting take on their relationship. 'Sasuke's Redemption under Sarutobi' is also good. It shows Sasuke trying to make amends with the village with Sarutobi's guiding spirit in mind. And 'The Hidden Power of the Trio' is a fanfic that gives a new perspective on the powers they possess and how they can be combined for the greater good.
In this type of fanfiction, it's possible that the story delves into Naruto's backstory and how being Sarutobi's son would have affected his childhood. Maybe he would have grown up with more guidance and support, which could have changed his personality. Instead of being the lonely outcast that he was in the original story, he could have been more confident from the start. The fanfiction might also introduce new characters related to Sarutobi that play important roles in Naruto's life. There could be new adventures and challenges that are unique to this new family dynamic, such as Naruto having to uphold the Sarutobi family name and legacy within the Hidden Leaf Village.
Perhaps he uses some ninja techniques like a shadow clone jutsu. He could make multiple clones to help him sort through and complete the paperwork quickly.
Naruto would probably be extremely hurt. He has always looked up to Sarutobi as a leader and a father figure. His first reaction might be disbelief, unable to accept that Sarutobi would do such a thing. Then he would likely feel a great sense of anger and betrayal. He might lash out and try to prove his innocence.
In some fanfictions, the previous Hokages could be main characters in relation to Mirai Sarutobi. For example, the First Hokage Hashirama Senju's spirit could appear to give Mirai some wisdom or a special power. Or the Third Hokage, being from the Sarutobi clan as well, could have left some hidden knowledge that Mirai discovers, making the old Hokage an important part of the story.
One great Anbu Naruto Sarutobi fanfiction is 'The Anbu's Hidden Mission'. It delves deep into Sarutobi's leadership within the Anbu and Naruto's unexpected role in a secret operation. The story is filled with intense action scenes and a touch of mystery.
Obviously, Naruto would be one of the main characters. And since it's about him being the son of Sarutobi, Sarutobi himself would be a crucial character. There would also likely be the usual Naruto characters like Sasuke, Sakura, Kakashi etc. as they would still be part of Naruto's life in the fanfiction, even with this new family relationship.
One popular sarutobi x naruto fanfiction might be those that explore a mentorship bond between them in a more in - depth way. For example, a story could focus on Sarutobi teaching Naruto some ancient and powerful jutsu that was once known only to the Hokage. This not only enhances Naruto's power but also deepens their connection.
One idea could be a time - travel fanfic where Sarutobi goes back in time and tries to prevent the rift between Naruto and Sasuke from ever happening. Another could be a fanfic where Naruto and Sasuke are transported to a parallel universe where Sarutobi is still alive and they have to work with him to get back home. Or a fanfic where Sarutobi trains Naruto and Sasuke together in a secret art that no one else in the village knows about.