Also, in the fanfic world, it could lead to Naruto being ostracized by the village. Since the Kyuubi is seen as a great threat, if Naruto willingly lets it take over, the villagers who already fear the Kyuubi might see Naruto as a traitor or a danger to them, causing him to lose the trust and support he has built up over time.
Another consequence could be that Naruto's body might not be able to handle the sudden takeover. The Kyuubi's chakra is immense and it could potentially damage Naruto's physical form. This could lead to him being seriously injured or even in a coma-like state as his body tries to adapt to the overwhelming power.
One possible consequence is that Naruto might lose control of his own actions. The Kyuubi is a powerful and often uncontrollable force. So, he could end up causing a great deal of destruction without meaning to. For example, he might attack his friends or allies in the heat of the moment as the Kyuubi's power overwhelms his own judgment.
Well, one main plot point might be Naruto's initial decision to let the Kyuubi take over. There must be some strong motivation behind it, like a powerful enemy that he can't defeat with his own strength. Another could be the reactions of his friends and the village. They would surely be shocked and some might try to stop him while others might try to understand his reasons.
Well, in fanfiction, the Naruto and Kyuubi fusion could lead to a change in how the ninja world views Naruto. He would be seen as an even greater threat or an even more powerful ally. For example, other villages might be more hesitant to engage in conflict with him. Also, his relationship with his friends could be affected. They might be in awe of his new power but also a bit worried about the Kyuubi's influence on him. And on a physical level, his appearance might change, perhaps taking on some of the Kyuubi's features, like his eyes or his hair color getting a more reddish tint.
One possible consequence is that the power balance in the ninja world is completely disrupted. With the Kyuubi's massive chakra and power running free, smaller villages might be constantly in fear of being attacked. Konoha, in particular, would have to find new ways to defend itself without relying on the fact that the Kyuubi is sealed within one of its shinobi.
Well, his relationship with the village could be affected. The villagers who were once afraid of the Kyuubi might be even more hesitant to accept Naruto now that he has the complete power. However, his closer friends like Sasuke and Sakura would stand by him. Sasuke might see Naruto as an even greater rival, but also a potential ally in protecting the village. And Sakura would be there to support Naruto both emotionally and in battle if needed.
One possible consequence could be chaos in the ninja world. With Naruto, a major force for peace, dead and the Kyuubi released, other villages might see an opportunity to gain power or territory. Villages that once relied on Naruto's protection would be vulnerable. Also, the Kyuubi, being a powerful and wild force, could start causing destruction on its own, without Naruto to control it.
If the fem Kyuubi gets control of Naruto in the fanfiction, one consequence could be that Naruto's relationships with his friends might be strained. His friends might not trust him anymore as they notice the change in his behavior under the Kyuubi's control. Another possibility is that Naruto could be used to cause chaos in the village. Since he's very powerful, the fem Kyuubi could use him to carry out her own plans, which might be harmful to the village and its people.
One potential consequence could be widespread destruction. The Kyuubi is an extremely powerful force. Buildings would likely be demolished, and many shinobi might be injured or killed trying to combat it. Another consequence could be a shift in the power dynamics within Konoha. Some might see Naruto as a threat, while others might try to use this situation to gain power themselves.
One possible consequence is that Naruto's body might not be able to handle Kurama's full power all at once. It could lead to physical harm or even death if not managed properly. Also, his relationships with Sakura, Sasuke and others would be in jeopardy as they might not recognize the Naruto under Kurama's control.
One consequence could be that he becomes extremely powerful. His physical abilities like strength, speed, and endurance are enhanced. He can also use more powerful jutsus with the extra chakra boost from the Kyuubi.
Well, if Kyuubi takes over Naruto in a fanfic, Naruto's physical appearance would probably change. His eyes might turn red like the Kyuubi's, and his chakra would be out of control. The story could focus on how the village reacts to this new threat. Some might see Naruto as a lost cause, while others, like his closest friends, would fight to save him.