Well, in this fanfiction, it might be about Naruto having some new kind of connection or role related to the Kyuubi. Maybe he gains new powers or has a different relationship with the Kyuubi's spirit. It could also involve how this new situation affects his relationships with his friends and the village.
He probably gains the ability to control the chakra of the Kyuubi more freely. This could mean enhanced strength, speed, and reflexes. He might also be able to use some of the Kyuubi's unique jutsu like the Tailed Beast Ball. His healing factor could be improved as well, allowing him to recover from injuries faster.
Well, his friends might initially be shocked. But Naruto, being Naruto, would probably use his new power to protect them more fiercely. His relationship with Sasuke could become even more complex. Sasuke might see Naruto as a greater threat or a new source of power to rival. For Sakura, she'd be worried about Naruto's well - being and how this new form affects him. And his other friends like Shikamaru would start to strategize around Naruto's new abilities, changing the dynamic of their teamwork.
Obviously, Naruto would be the main character. Since it's about him being the new Kyuubi. And his friends like Sasuke, Sakura, Kakashi would also be important characters. They would likely be involved in how they react to Naruto's new state and how they support or oppose him.
One idea could be exploring the Kyuubi's new powers in the fanfiction. Maybe it gains the ability to communicate telepathically with all the villagers, leading to a whole new dynamic in the Hidden Leaf. Another could be a story where the new Kyuubi forms a unique bond with Naruto's child, if there is one in the fanfiction. This bond could be the key to a new era of peace in the ninja world.
He might gain enhanced physical strength. Since the Kyuubi is known for its great power, Naruto could have a boost in his melee combat abilities. For instance, his punches and kicks could be more powerful, allowing him to take on stronger opponents more easily.
For character development in a 'Naruto New Kyuubi Fanfiction', Naruto could start to see the Kyuubi not just as a source of power but as a sentient being with its own feelings and desires. This realization could make him more empathetic and also change his approach to using the Kyuubi's power. He might become more cautious and try to negotiate with the Kyuubi instead of just forcefully taking its chakra.
He might gain enhanced chakra control. Since he has the Kyuubi's soul, he could have better access to the Kyuubi's chakra reserves and be able to manipulate it more precisely. Maybe he could also gain some of the Kyuubi's natural abilities like better senses, especially smell, which could help him in tracking enemies or finding things.
Yes, in some fanfictions, Naruto is often depicted as the Kyuubi or having a very close connection to it. This can lead to really interesting and unique storylines that deviate from the original plot.
One common plotline is the Kyuubi teaching Naruto new and powerful jutsu. Since the Kyuubi has a vast amount of chakra and knowledge, it could share unique techniques with Naruto that are not part of the regular ninja training. Another plotline could be the Kyuubi's influence on Naruto's relationships. For example, some fanfictions explore how Naruto's connection with the Kyuubi affects how his friends and villagers perceive him. It can also lead to some interesting character development as Naruto has to learn to control the Kyuubi's power without being consumed by it.