His character could be developed by showing his adjustment to the Fairy Tail world. He could start off as a loner, but gradually open up to the members. His backstory as a ninja could be explored further in relation to the new environment, like how his past actions affect his new relationships.
One possible plot could be that Itachi, seeing Naruto's potential and his importance for the future of the Hidden Leaf, decides to secretly train him. Itachi might teach Naruto advanced jutsu, especially those related to chakra control and unique Sharingan - inspired techniques. Naruto, under Itachi's tutelage, would grow not only in power but also in his understanding of the ninja world's complex politics and the Uchiha clan's history.
One possible plot could be that Itachi, with his mysterious and alluring charm, starts by casually interacting with Sakura in the Hidden Leaf Village. He might save her from a small danger, which makes Sakura curious about him. Then he begins to share his deep thoughts about the ninja world with her, gradually drawing her in with his intelligence and different perspective.
Well, perhaps Sarada could be initially in awe of Itachi. She might learn some unique jutsu techniques from him in the fanfiction. It could also be a scenario where Itachi gives her some sage advice on how to handle her own powers and responsibilities within the Uchiha clan.
In an Itachi Uchiha love story, Itachi could be in love with a foreign diplomat who visits Konoha. They have a whirlwind romance. However, his status as an Uchiha and the secrets he holds start to create problems. His love is tested when his clan's actions put the village in danger. He has to decide whether to side with his love or with his village, leading to a complex and tragic love plot.
One possible plot could be that Naruto, after learning more about Itachi's true motives and sacrifices, decides to join forces with Itachi in the fanfiction world. They might team up to take on a new common enemy, perhaps an even more powerful Akatsuki member or a threat to the Hidden Leaf that the village's regular forces can't handle alone. Naruto's positive energy and determination could blend well with Itachi's strategic mind and powerful jutsu.
Well, it could be that they meet by chance in a hidden forest. Minato might initially be cautious as he's aware of Itachi's reputation in the Akatsuki. But then they could start sharing their stories, like Itachi talking about his family's situation in Konoha and Minato sharing his experiences of protecting the village. They might even find some common ground in their love for their respective villages.
Perhaps Itachi would teach Naruto some advanced jutsu techniques. Naruto is known for his Rasengan and later on Sage Mode, but Itachi could introduce him to more subtle and strategic ninjutsu. Itachi's experience in combat and his intelligence would make him a great teacher in this regard. He could also teach Naruto about how to better analyze an opponent's weaknesses during a fight.