One popular storyline could be the future child having to deal with the legacy of Naruto. For example, they might struggle to live up to their father's great name. Another could be the child using new and unique ninja techniques that combine the skills of their parents and create a new style. Also, stories often explore the relationships the future child has with the old friends of Naruto, like how they interact with Sasuke or Sakura who are now much older and wiser.
Writers often start by giving the future children a distinct personality trait. For example, if the child is Naruto's son, he might inherit Naruto's determination but also have a more calm and collected side from his mother. They also develop their appearance, maybe giving them Naruto's blond hair but with different colored eyes. Another way is by showing their relationships with other characters early on. If they're shy around new people but open up quickly to family friends, that tells a lot about them.
The future child's character can be developed by showing their struggle to live up to their parents' reputations. Since Natsu and Lucy are well - known in the Fairy Tail world, the child might feel pressured. This internal conflict can shape their personality. For example, they could be initially shy but gradually become more confident as they prove themselves.
Their relationship would likely become more serious and responsible. They'd have to put aside some of their youthful antics as they now have a child to think about, even if it's from the future. There would be a new level of trust and understanding as they work together to deal with the situation.
In some Naruto fanfictions, Naruto babysitting Sakura as a child could be really interesting. It might show a different side of their relationship. Maybe Naruto has to take care of Sakura because her parents are away or something. He could teach her some basic ninja skills in a fun and childish way, like how to throw a kunai accurately using a game.
In fanfiction, such a plot is just a creative and often non - canonical idea. Naruto is canonically Minato's legitimate son. In the fanfic's context, it might be used to explore different character dynamics and add a layer of drama. But it goes against the original story's established relationships.
One common theme is friendship. Since they are such important characters in the Naruto series, fanfictions often explore how they could have been closer friends as children. Another theme is rivalry, showing how their competitive nature started at a young age.
There's a chance he could meet an older and wiser Kakashi. Kakashi might have new insights and stories to share with Naruto from all the years that have passed. And also, he could run into future shinobi who look up to him as a legend from the past.
He might be really surprised. Naruto is used to his own world and the fanfiction could show things he never imagined. For example, if the fanfiction has his kids achieving great things in new ways, he'd be proud yet a bit shocked at how creative fans can be.
He might be shocked at how the village has developed. In some fanfictions, the village could have advanced technology. Naruto, being from a more traditional ninja world, would likely be both amazed and a bit confused at first.