Kabuto could also be a good antagonist. After he gained all those powers and knowledge, he might target Naruto's six - tails form. He could use his medical ninjutsu to try and manipulate Naruto's transformation or even try to extract the power of the six - tails for his own use. Since he has the ability to mimic other ninja's techniques, he could be a formidable foe against Naruto in six - tails form.
Sakura could be a great choice. She has strong medical ninjutsu skills and a no - nonsense attitude. She could help the six - tails jinchuriki when they get injured during battles against the power of the six - tails or external enemies. Also, her growth as a character could be further explored as she tries to understand and support the jinchuriki.
One idea could be the six - tails jinchuriki's struggle to control the power. For example, they constantly have to battle the inner urge of the six - tails to go on a rampage. Another plot could involve the jinchuriki being hunted by an evil organization that wants to extract the six - tails' power for their own malicious use. They would then have to fight and outwit this organization while also dealing with the social ostracism that often comes with being a jinchuriki.
Well, a cool plot for Naruto six - tails form fanfiction might be about time travel. Naruto accidentally travels back in time while in six - tails form. He then has to figure out how to hide his form from his younger self and the people in the past. At the same time, he could use his knowledge from the future and the power of the six - tails to prevent some great disasters from happening in the past, which would change the future in unexpected ways.
One possible reason could be some kind of strange chakra infusion. Maybe he comes into contact with a powerful and mysterious chakra source that mutates his body in a way that causes tails to grow. Another reason might be related to some ancient curse or prophecy. It could also be the result of a new jutsu he attempts that goes wrong and has unforeseen physical consequences.
In certain fanfiction, Naruto is indeed the Ten - Tails. This could be a really cool concept as it combines Naruto's already powerful nature with the ultimate power of the Ten - Tails. It might lead to stories where Naruto has to struggle with the dark side of such power, or he could use it to bring about a new era of peace in the ninja world. Maybe he would have to face off against old enemies who are now even more afraid of his new - found strength.
Maybe through new jutsu or abilities. The fanfiction could give Naruto some unique power that allows him to communicate or negotiate with the Nine - Tails on a different level. He could use this power to show the Nine - Tails a different perspective, like the potential for harmony between them instead of constant struggle.
Yes, in some fanfictions, Naruto is often depicted as having a very special connection to the Nine - Tails that goes beyond the normal relationship in the original story. For example, he might be able to fully control the Nine - Tails' power in ways not shown in the canon, or they could have a mental bond that allows for unique forms of communication and cooperation.
Well, initially, Naruto might show kindness towards the Nine - Tails despite it being a powerful and somewhat feared entity. He could try to communicate with it on a deeper level. The Nine - Tails, in turn, might be intrigued by Naruto's tenacity. As time passes, they begin to trust each other more. Naruto may share his dreams and fears with the Nine - Tails, and the Nine - Tails might start to see Naruto as someone worthy of its friendship.
A new character could be introduced as the host. This character could be from a hidden clan with a special ability to bond with the Eleven Tails. They would bring a fresh perspective to the story, and their journey of coming to terms with the power of the beast and its implications in the Naruto universe would be an exciting plotline.