Well, in this 'Boruto goes to the past fanfiction', Boruto could potentially change some events in the past. Maybe he tries to prevent some of the tragedies that his father and the others had to endure. But he would have to be very careful because any small change could have big consequences for the future. He might also learn some long - lost ninja techniques that were forgotten in his time, and bring them back to the future to make Konoha even stronger.
His presence could create a butterfly effect. Small actions he takes might change the future. For example, if he teaches a young ninja a new technique, it could change how battles are fought in the future.
In the 'Boruto goes rogue fanfiction', it could be that he discovers a dark secret about the village leadership. This makes him lose faith in the system and go rogue. He might then seek out other outcasts or those with similar grievances to form his own group to oppose the village's unjust ways.
It could be a new character, someone who has a vendetta against Boruto and drives him to go rogue by framing him for various crimes. This new antagonist might have their own motives related to taking over the Hidden Leaf or causing chaos in the shinobi world.
Well, Boruto could be very inspired. Naruto's past is full of struggles, from not having parents around to being constantly underestimated. When Boruto discovers this in the fanfiction, he might realize that his own problems are not as big as he thought. He could be motivated to work harder and not take for granted the things he has, seeing how much Naruto had to fight for everything.
It could be the Kara organization. They've been shown to be interested in Boruto's Karma mark in the original series, so they might have finally made a move to abduct him in the fanfic.
Boruto might be in awe. He has always known his father as the Hokage, a powerful and respected figure. Seeing Naruto's past full of struggles, loneliness, and determination would make him realize how far his father has come. It could also make Boruto more empathetic towards Naruto and perhaps inspire him to be more like his father in some ways.
Well, often in these fanfictions, Boruto watching the past can lead to him learning about the great battles that his predecessors fought. He may witness the Fourth Great Ninja War and see the heroic deeds of his father and the other ninja. This could either make him feel pressured to live up to their legacies or give him the motivation to carve out his own path in the ninja world, different from what has been done before.
Perhaps in this 'Boruto goes missing fanfic', Boruto is lured away by a mysterious figure who claims to have information about his future or his father Naruto's past. He follows this figure without thinking, only to find himself in a strange and dangerous place. His disappearance then sets off a chain of events in the village. People start to suspect that there might be a traitor among them who helped Boruto disappear. His teammates, like Sarada and Mitsuki, would then start their own investigation to find him, facing not only external threats but also internal doubts and suspicions within the village.
In the 'Boruto Goes Kidnapped' fanfic, it could be that the kidnappers are after some special power that Boruto has. His father Naruto would be extremely worried and start gathering all the resources in the village to find his son. Meanwhile, Boruto might be trying to escape on his own, using any opportunity he gets.