Well, one possible plot could be that Naruto is somehow magically transformed into a dragon bijuu. He might then have to learn to control his new form and powers. Maybe he'd face off against enemies who are both intrigued and threatened by his new state. His friends could be initially shocked but then try to help him adapt.
A plot for this fanfiction could start with Naruto having a strange encounter with an old sage who warns him of a coming danger. But during the encounter, some sort of magic backfires and Naruto turns into a dragon bijuu. His new dragon form might attract the attention of other bijuus who see him as either a threat or a potential ally. Naruto would have to navigate this new world of being a dragon bijuu, dealing with his own internal struggles about his identity, all while trying to keep the peace in the ninja world. He could also discover that his new form has a connection to an ancient prophecy that foretells of a great battle between the forces of light and darkness, and he is now a key player in that prophecy.
In this fanfiction, if Naruto becomes a dragon bijuu, perhaps it's due to some ancient curse or a powerful jutsu gone wrong. His new form could give him abilities like flight, super - strength, and the ability to breathe fire. The plot could involve him trying to find a way to reverse the transformation while also using his new powers to protect the village from a new and powerful threat that only his dragon form can defeat. For example, a group of rogue ninjas who have teamed up with a powerful dark entity.
Well, perhaps in the 'naruto becomes a wolf bijuu fanfiction', Naruto is transformed into a wolf - like Bijuu form due to some dark magic or a strange experiment gone wrong. His friends initially don't recognize him, and he has to struggle to control this new form while also trying to show them it's still him. He may learn new jutsus that are unique to this wolf - bijuu form and use them to protect the village from new threats that are too powerful for his normal form.
It could be an ancient sage. In Naruto lore, there are sages who have had a great influence on the world. An ancient sage could be the one who created or fathered the bijuu. Maybe he had some great power and knowledge that allowed him to bring the bijuu into existence.
One possible plot could be that Naruto is exposed to some ancient and dark magic during a mission. This magic slowly transforms him into a Youkai. As he turns, he starts to struggle with his new instincts and powers. His friends initially don't recognize him and think he's a new threat. Naruto has to find a way to control his Youkai side and convince his friends that he's still himself.
Well, without actually reading it in detail, generally in such a fanfiction, Naruto might have some extraordinary adventures related to his control over the bijuu. He could be using their powers in unique ways to fight enemies, or perhaps he's on a journey to master their full potential and face new challenges that come with that power.
Well, having two bijuu would likely make Naruto extremely powerful. He could potentially combine their unique chakra natures and abilities in combat. For example, if one bijuu has a fire - based ability and the other has a water - based one, he might be able to create new and unexpected jutsu by mixing them. Also, it would change his standing in the ninja world. People would probably be more in awe or more fearful of him, depending on their stance towards Naruto.
It could be Shukaku. Since Shukaku was one of the first bijuu introduced in the series and has a sand - based power, it would be an interesting addition to Naruto's arsenal. Naruto's positive and energetic personality could also have an impact on Shukaku's usually grumpy and solitary nature.
One possible plot could be that an ancient and powerful tailed beast is released. Naruto and Hinata, in their quest to protect the village, end up being the only ones able to bond with it. They then have to learn to control the new power within them while facing opposition from other villages who fear their combined strength.
One possible plot could be that Naruto and Hinata are faced with a great threat to the ninja world that is beyond the power of normal shinobi. In their quest to protect everyone, they discover a hidden ancient power that transforms them into gods. As gods, they have to deal with new responsibilities and also face some jealousy from other powerful beings in the ninja world.
In this fanfiction, it could be that Naruto is found to be a prince of a foreign land during one of his missions. As a prince, he is expected to marry for political alliances. However, Naruto is torn between his duties as a prince and his feelings for his friends back in Konoha. He has to find a way to balance both worlds and maybe even change the traditional ways of the foreign kingdom.
In a fem Naruto becomes Hokage fanfiction, the plot could revolve around her unique approach to leadership. Maybe she focuses more on diplomacy and building relationships between different ninja clans. She could use her empathy, which might be emphasized more as a female character, to resolve long - standing disputes. And when it comes to facing threats to the village, she uses her own brand of ninjutsu, which could be a mix of her father's and her own unique feminine style. Eventually, she earns the title of Hokage by uniting the village in a new way.