Well, it could be about Naruto having the ability to see ghosts in a fan - made story. Maybe he encounters different kinds of ghosts, some friendly and some not so much. It might also explore how this new power affects his relationships with his friends and his role as a ninja.
One common theme is the idea of Naruto having to overcome his fear of the monsters. Since he's used to dealing with normal ninja threats, these strange and often terrifying monsters present a new challenge.
It could be a new character, perhaps someone from a far - off land who has a grudge against Naruto's future self for some reason. This character might be extremely powerful and has plans to destroy everything Naruto holds dear. When Naruto sees this future, he has to find a way to stop this new threat before it even begins to form.
Maybe in the fanfic, Naruto sees a future where Konoha is destroyed. This makes him determined to change the future. He could start by strengthening the village's defenses, forging new alliances, and also trying to figure out the root cause of the destruction in the future he saw. He might also try to uncover any hidden threats within the village that could lead to such a catastrophe.
One common theme is self - discovery. Since Naruto sees demons, he often has to figure out what it means for him personally. Another theme is the battle between good and evil. Naruto usually has to decide whether the demons he sees are all bad or if there are some that can be redeemed.
In the 'naruto sees dead people fanfic', it might be that Naruto's encounters with the dead are used to reveal hidden aspects of the Naruto universe. For example, he could meet dead villains and understand their motives better, or he could see the spirits of his ancestors who guide him in his journey to become a stronger ninja. It could also be a way to bring back fan - favorite characters in a different way, even if they are dead in the original series.
Naruto is the central character, no doubt. Hinata could be important as well. If Naruto sees a future related to his family or his relationship with Hinata, she will play a significant role. Additionally, the Hokage, like Tsunade or whoever is in charge at that time, would be important as Naruto may need to report the future he saw to the village leadership to take collective action.
Well, perhaps Naruto sees the future where his friends are in great danger. So he tries to change the course of events. He might start to make different decisions in his present to avoid the bad future he has witnessed. For example, he could try to resolve conflicts with certain characters earlier to prevent future wars.
Naruto might meet his future children. He would be able to see what kind of people they are and what their dreams and aspirations are. It would be an emotional moment for him, seeing his family in the future.
Naruto might be shocked at first. He could stand there frozen, unable to believe what he's seeing. His face would probably show a mix of confusion and hurt.