Madara Uchiha could also be a main antagonist in this fanfiction. He has grand plans for the ninja world and the released Kyuubi could be a key part of his scheme. Since Naruto is dead and can't oppose him, he might try to use the Kyuubi to reshape the world according to his vision. He has the power and the ambition to be a major threat in this situation.
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.
Well, a common theme in such fanfictions is the chaos that ensues. The release of the Kyuubi is a major event. Villages could be destroyed, and Naruto has to learn to control this power quickly. Some fanfictions might focus on the training he undertakes to master the Kyuubi's power, perhaps with the help of some unexpected mentors.
Obviously, Naruto is the central character as it's about the Kyuubi being released from him. Sasuke also often plays a crucial role. He might be concerned about Naruto's new state, or he could be one of the characters trying to either help or stop Naruto depending on the plot.
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.
In many Naruto fanfictions, Naruto might have developed some new and unique abilities that the Kyuubi has no defense against. This could make the Kyuubi, which is used to being a dominant and feared force, feel vulnerable. For example, if Naruto has the power to nullify the Kyuubi's chakra or to manipulate it in a way that goes against the Kyuubi's will, it would be a cause for fear.
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.
Well, in such fanfictions, Naruto often relies on his ninja skills, along with the support of his friends and mentors. Sometimes, he also taps into hidden reserves of chakra and unlocks special abilities to battle the Kyuubi.
Well, in Naruto fanfiction, the Kyuubi often has the power of destruction. It can unleash huge amounts of raw chakra that can level mountains or create massive shockwaves. The Kyuubi's power can also be used for healing in some fanfictions. Since it has such a large amount of chakra, it can be used to heal the jinchuriki's wounds, even from near - fatal injuries. Also, in certain fan - made stories, the Kyuubi has the ability to communicate telepathically with the jinchuriki, providing wisdom and knowledge from its long existence.
I really liked 'Fem Kyuubi's Bond with Naruto'. In this fanfic, the fem Kyuubi forms a deep emotional bond with Naruto. The author does a great job of showing how they support each other through various challenges. It has some really cool fight scenes where the fem Kyuubi's unique abilities are shown, which makes for an exciting read.