Well, the plot could be that Hinata's twin brother is sent on a secret mission. He discovers a conspiracy within the village that could threaten the Hyuga clan. He has to gather evidence and allies, and Naruto could be one of the key allies. They might have to fight against some rogue ninja who are part of the conspiracy.
One possible fanfiction idea could be that Hinata's twin brother is a prodigy in a different ninja art than Hinata. He might be more focused on offensive taijutsu techniques, while Hinata is known for her gentle fist. This could create an interesting dynamic within the Hyuga clan as they both grow and develop their skills.
The plot could involve Naruto protecting Hinata from the Hyuga clan's strict traditions. Since he's not bound by those traditions as her brother, he could fight against the elders who want to keep Hinata in a subservient role.
A plot could be that Hinata is bent over a garden, planting some flowers. Naruto, being curious, comes to see what she is doing. As he approaches, he startles her a bit. They then have a conversation about the beauty of nature and how Hinata finds peace in gardening. This could be a sweet moment that shows their different hobbies and how they can still connect on a deeper level.
In a fanfiction, Robb Stark's twin brother might be a seer. He has visions of the future that are different from Bran's. While Robb is fighting his wars, his twin is trying to use his gift to prevent disasters. For example, he might see the Red Wedding in advance and try to warn Robb. However, due to the chaos of the war and disbelief from others, his warnings go unheeded. This could lead to a story full of regret and a new determination to avenge Robb's death and change the fate of the Stark family.
One possible plot could be that Naruto accidentally stumbles upon Hinata in the hotspring. Hinata is initially shy and embarrassed, but Naruto, being his oblivious self, doesn't fully understand the situation at first. Then they start having a conversation about their ninja training and goals, which deepens their bond. And Hinata realizes that Naruto has a newfound respect for her as a strong ninja.
The plot could start with Naruto finding out about his true identity as Lucifer's twin. This revelation could send shockwaves through the DxD universe. He might then be forced to choose sides in the ongoing battles between angels, devils, and other supernatural beings. Along the way, he could use his Naruto - like determination and training to gain respect and allies, while also trying to understand his new - found connection to Lucifer and the implications it has for his own destiny. As he navigates this new world, he could introduce concepts from the ninja world, like honor and loyalty, which could change the dynamics of the DxD universe.
If Naruto and Hinata were twins in a fanfiction, their combined strength could be formidable. Naruto has his vast chakra reserves and the Nine - Tails' power. Hinata has the Byakugan and her gentle fist technique. Together, they could use Hinata's Byakugan to scout and plan attacks while Naruto uses his brute force. They could also combine their chakra in some unique ways, perhaps creating new jutsu. Their teamwork would be enhanced due to their twin bond, allowing them to anticipate each other's moves better.
The original Naruto story would be turned upside down. Naruto being Hinata's twin would affect his relationship with Sasuke too. Maybe instead of his intense rivalry with Sasuke, Naruto would focus more on family matters. His dreams might also change as he would be part of the Hyuga clan. The Hyuga clan's secrets and techniques could be shared with Naruto more easily. This would give him an edge in battles and change how he approaches his ninja career. His friends like Shikamaru and Kiba might view him differently as well, since he would now be associated with the Hyuga clan rather than just being the orphaned Uzumaki.
If Naruto were Sakura's twin brother, the story would be very different. Naruto would have someone in his family from the start, which would have affected his personality. He might not be as eager to seek attention and approval as he was in the original story. In terms of their ninja training, they could have learned from each other. Sakura might have taught Naruto some of her book smarts when it comes to ninjutsu theory, and Naruto could have shown Sakura some of his more unorthodox but effective combat techniques. Their relationship with Kakashi as their sensei would also change, as Kakashi would have to deal with the unique bond between the two siblings.
The plot could involve Naruto using his knowledge of chakra to diagnose Rias' brother's illness. He might discover that it's not a normal sickness but something related to the supernatural nature of their world. For example, his chakra flow could be disrupted by a dark magic spell.