One interesting plot could be that Hiashi discovers Naruto has some hidden connection to the Hyuga clan. This would make Hiashi take a special interest in Naruto, and he might start training Naruto in Hyuga - related skills.
A great plot would be if Naruto is sent to negotiate with Hiashi on behalf of the Hokage. The two have different views on how to deal with a new threat to the village. Naruto believes in a more inclusive and open - minded approach, while Hiashi is more cautious and traditional. Through their discussions, they both learn from each other and come up with a new strategy to protect the village. This would show how two very different characters can find common ground and grow from their interactions.
Maybe there is a prophecy in the Hidden Leaf Village that only Naruto and Hiashi together can fulfill. They are initially unaware of it, but strange events start to happen that lead them to cross paths. As they start to work together to figure out what is going on, they discover that they each hold a key to a great power that can save the village from a powerful and ancient evil. Along the way, they have to overcome their personal differences and trust issues to succeed.
One possible plot could be that Naruto gains a whole new family structure. Hiashi might train Naruto in the ways of the Hyuga clan, which could make Naruto an even more formidable ninja. He would also be exposed to the Hyuga's strict traditions and might have a different view on the ninja world. Maybe he'd form a closer bond with Hinata earlier as they'd be siblings in this scenario.
Perhaps in this fanfiction, Naruto meets Hiashi during a time of crisis in the Hidden Leaf Village. Hiashi, being an elder and a respected figure, is involved in the village's defense plans. Naruto, eager to help, wants to be part of the action. Hiashi initially doubts Naruto's abilities but is soon proven wrong. They then work side by side, with Naruto's Uzumaki chakra and Hiashi's Hyuga skills combining to create a powerful defense against the enemy.
Well, it could be about Naruto growing up in the Hyuga clan. Maybe he discovers his true parentage early on and has to deal with the expectations and politics of the clan. He might learn the Gentle Fist technique in a different way than Neji or Hinata.
Maybe Hiashi adopts Naruto because he realizes that Naruto is a key to uniting the village. As Naruto becomes part of the Hyuga family, he starts to influence the clan's view on outsiders. He might introduce some new training methods that he learned from Jiraiya. Naruto could also have a role in protecting the Hyuga's secrets, like the Byakugan. He would grow in a different environment, and this would change his relationships with characters like Sasuke and Sakura in new and unexpected ways.
One interesting Naruto and Hiashi fanfiction could be about Hiashi training Naruto in some secret Hyuga techniques. Maybe Naruto has to prove himself to Hiashi first, and through a series of trials, they form an unlikely bond.
One possible motive could be a misunderstanding. Maybe Hiashi mistakes Naruto for an enemy who has infiltrated the village in disguise. Another reason could be related to clan politics. If Naruto somehow gets involved in a situation that threatens Hiashi's clan interests, Hiashi might take extreme measures.
Maybe in the fanfic, there is a dark force that tries to manipulate Hiashi into attacking Naruto. The fanfic could explore how Naruto tries to reach out to Hiashi, to show him that they are being played. Along the way, they have an intense battle where Naruto shows off his new jutsus and Hiashi uses his clan's most secret techniques. In the end, they realize they were on the same side all along.
The plot might involve Inuyasha being transported to the Naruto universe. At first, he's confused and a bit hostile. However, Naruto, being the friendly and curious guy he is, tries to befriend Inuyasha. They could end up on a mission together to save a village in the Naruto world. Inuyasha would use his demon - slaying skills while Naruto uses his shadow clones to distract the enemy. It would be a story full of action, friendship, and a bit of comedy as they learn to work together despite their differences.
A possible plot could be that Naruto is sent back in time and meets Hashirama and Madara during their prime. He tries to prevent the feud between them from escalating. Naruto, with his modern - day knowledge and ideals, attempts to show them a different path for the ninja world. He might have to prove himself in battle against them first to earn their respect and then start to influence their decisions.
Perhaps in this fanfiction, the Shadow Realm from Yugioh has some sort of connection to the Tailed Beasts in Naruto. The characters could be on a quest to seal the Shadow Realm and prevent it from corrupting the Tailed Beasts. This would involve the Yugioh characters using their card - based magic and the Naruto characters using their chakra - based powers in a coordinated effort. Maybe the Millennium Items play a role in controlling or understanding the power of the Tailed Beasts.