In this kind of fanfiction, Naruto's training would take a whole new turn. Instead of just trying to control the Nine - Tailed Fox's chakra, he would be learning to be the Nine - Tailed Fox. He might have to adapt to new instincts and ways of thinking, which would be a great challenge for him but also a chance for character growth.
Naruto might gain new physical abilities like enhanced speed and agility as a fox. He could run faster through the forests and jump higher. The Fem Kyuubi could be his mentor in using these new skills.
Well, if Naruto becomes the Kyuubi in the fanfiction, he would likely have an overwhelming amount of power. He might be able to defeat his enemies with ease. But he would also face the struggle of controlling such a powerful and wild force inside him. Maybe his friends would be both in awe and a bit scared of him at first.
Well, if Naruto becomes Mikoto, he would be a female in the body of Mikoto. He could bring his own values and experiences as Naruto. This could potentially change the relationship dynamics within the Uchiha clan. He may try to bridge the gap between the Uchiha and the rest of the village in a way that Mikoto might not have been able to do in the original story due to her own limitations and the circumstances of the time.
He might gain new and unique powers. For example, his regular jutsu could be combined with prototype - like abilities such as enhanced physical strength and the ability to quickly adapt to any situation.
In this kind of fanfiction, Naruto might gain even more incredible power. He could have enhanced physical abilities like super strength and speed, as well as new jutsu related to the bijuu's nature. For example, if he becomes the Nine - Tails bijuu, he might be able to use the Tailed Beast Ball more effectively and on a larger scale. His appearance might also change, perhaps taking on some of the characteristics of the bijuu, like fox - like features if it's the Nine - Tails. This could lead to new relationships and dynamics with other characters. His friends might be in awe of his new power, while his enemies would be even more fearful.
Well, in fanfiction, anything is possible. Maybe Naruto gets transported to the Sekirei world through some sort of magic or a strange portal. This could be the start of his journey to become a Sekirei. It could also be due to a curse or a wish gone wrong that transforms him into a Sekirei - like form.
Well, if Naruto becomes the reaper in fanfiction, he would probably have a whole new set of powers. He could start reaping souls in the Naruto universe, which would be a huge change. Maybe he'd use his new reaper abilities to deal with the more dangerous enemies in a different way, like sending their souls to some sort of afterlife realm.
If Naruto becomes a Digimon fanfiction, it could be really interesting. Naruto might find himself in the digital world, trying to adapt his ninja skills to deal with Digimon. He could form an unexpected bond with a Digimon partner, like how he did with his friends in the Naruto world. And his sense of justice would surely lead him to fight against any evil Digimon that threaten the digital world.
In a Naruto becomes a Terminator fanfiction, it could start with some sort of time - travel or interdimensional rift. Maybe a jutsu gone wrong sends Naruto to a world where the Terminator technology exists. Then, Naruto, with his ninja skills and strong will, might adapt to the new environment. He could use his chakra in unique ways combined with the advanced weaponry of the Terminator world.
In 'naruto becomes a giant fanfiction', Naruto could become a symbol of both fear and hope. His giant stature might intimidate his foes right away. He could potentially be used as a weapon by the Hidden Leaf Village in a more direct way. Also, his friends would have to adapt to his new form, and there could be some really interesting interactions as they figure out how to communicate and fight alongside a giant Naruto.