It could be an unknown relative of Naruto. Maybe someone who has been living in a far - off place and just discovers their Uzumaki heritage.
Perhaps it's a character created specifically for the fanfiction. A young Uzumaki with unique abilities and a different upbringing compared to Naruto. They could have grown up in a place where the Uzumaki culture was still strong, and have knowledge that Naruto lacks.
Well, they might share their Uzumaki clan stories. Naruto could learn something new about his heritage from this other Uzumaki fan. Maybe they'd team up for some kind of mission related to the Uzumaki clan's secrets.
One possible plot could be that Naruto time - travels and meets Mito Uzumaki. Mito could sense Naruto's strong chakra similar to Hashirama's. She might mistake him for a descendant of Hashirama at first. Then Naruto could learn about the origin of the Uzumaki clan from her and how they were powerful in sealing techniques. This encounter could also lead to Naruto getting some ancient knowledge about chakra control or sealing that he could use in his own time.
Perhaps Naruto would find ancient Uzumaki artifacts in the fanfic. These artifacts could have powerful abilities. He might have to face off against enemies who also want these artifacts for their own evil purposes. And through his interactions with the Uzumaki clan, he could gain new friends and allies who would stand by him in future battles.
One possible plot could be a story of friendship. Karin, with her unique abilities, could team up with Naruto in some mission. They might start off not getting along well, but as they face challenges together, they develop a deep bond. For example, they could be on a mission to rescue some kidnapped villagers. Karin's sensory skills and Naruto's combat power would complement each other.
Maybe Naruto would meet some young Uzumaki clan members who look up to him. They would be inspired by his strength and his will to protect the village. Naruto could then take on the role of a mentor, teaching them the values he learned in Konoha and also some of his own ninja techniques.
Another possibility is that it's an unknown Uzumaki from a far - off land. This Uzumaki could have heard about Naruto's power and decided to kidnap him in order to bring back Naruto to their land and use his power to solve some long - standing problems in their own community, like a shortage of resources or protection against an external threat.
The Akatsuki could also be antagonists in this fanfiction. They might see the Uzumaki bloodline as a threat or as a valuable asset to their goals. So they would target Naruto not just as a jinchuriki but also as the heir of the Uzumaki clan.
Well, in this fanfiction, Shinachiku Uzumaki might show off some unique ninja skills that he's inherited. Maybe he and Boruto could go on an adventure together, like exploring an ancient, mysterious ninja temple filled with traps and hidden jutsu scrolls.
It could be someone who is jealous of their new - found bond. Maybe a rival of Uzumaki who doesn't want him to have such a powerful ally in his sister.
If Naruto joined Fairy Tail, it would be really interesting. He has a lot of chakra which could be something new in the world of Fairy Tail. He might get into some friendly rivalries with the strong mages there. Also, his ability to make friends easily would help him bond with the Fairy Tail guild members quickly. And his dream of becoming Hokage could translate into a new big dream within the Fairy Tail context, like becoming the strongest mage or something.