One interesting type of original character is a wandering ninja who has been on a quest to find the true nature of the Nine - Tailed Fox. This character might cross paths with Naruto and share their knowledge or experiences. Another is a young girl who can communicate with the Nine - Tailed Fox on a spiritual level, which causes Naruto to be both intrigued and a bit jealous. And then there are the members of a secret organization that wants to harness the power of the Nine - Tailed Fox for their own dark purposes, and they create original characters within this organization who have unique abilities and motives.
Well, for a 'naruto the nine tailed fox fanfiction', you should definitely consider including Itachi. His actions and his connection to Sasuke can be intertwined with Naruto's story involving the Nine - Tailed Fox. Tsunade is also a popular choice. As the Hokage, she has power and influence over Naruto and any situation regarding the Nine - Tailed Fox. Shikamaru is another character that can be interesting. His intelligence can be used to strategize around the power of the Nine - Tailed Fox. And of course, Gaara. He also has a tailed beast within him, so there could be some great interactions between him and Naruto regarding their shared experiences with tailed beasts.
One interesting fanfiction could be about the Nine - Tailed Fox's origin before it was sealed in Naruto. Maybe it was a powerful and free - spirited being in a different realm, and the story could explore its relationships with other mythical creatures there.
When it comes to Sasuke, the Nine - Tailed Fox Faunus could be seen as a threat at first. But as the story progresses, they might find common ground in their pursuit of power and their desire to protect their own kind. The faunus could show Sasuke a different side of power, one that is more in tune with nature.
One interesting plot could be Naruto fully transforming into the Nine - Tailed Fox during a battle against a powerful enemy. His friends are initially shocked but then try to find a way to bring him back to his senses.
One idea could be exploring the relationship between Naruto and the Nine - Tailed Fox in more depth. Maybe Naruto has to enter the fox's mind - scape and they have a long conversation about their fates being intertwined. Another plot could be a 'what if' scenario where the Nine - Tailed Fox was released earlier in Naruto's life and how he would deal with it without as much training. A third idea is to have the Nine - Tailed Fox take on a human form and accompany Naruto on his adventures, causing all sorts of chaos and also some unexpected moments of friendship.
One interesting plot could be Naruto's struggle to control the power of the Nine - Tailed Fox when he releases it. He might have to face inner demons and the fear of losing himself to the fox's power.
You could create a character who is a descendant of an ancient clan that has a special connection to the Nine - Tails Chakra. This character could be a rival to Naruto at first, thinking that Naruto doesn't deserve the power of the Nine - Tails. Another option is a mysterious healer who can manipulate the Nine - Tails Chakra in a unique way to heal even the most severe wounds.
One interesting character often paired with the seven - tailed jinchuuriki is Naruto. Given Naruto's own experience as a jinchuuriki, they can bond over their shared struggles. Another could be Kakashi. His wisdom and combat skills can provide support and guidance to the seven - tailed jinchuuriki. Also, Sakura might be paired with them. Sakura's medical skills could come in handy in case the seven - tailed jinchuuriki gets injured during battles or power - related incidents.
There are fanfictions where the Nine - Tailed Fox has a split personality. One side is the fierce and powerful beast, and the other is a more gentle and understanding entity. Naruto has to deal with both sides, which creates a very complex and different kind of relationship compared to the original series. This can lead to some really interesting character development for Naruto as he tries to balance and understand this unique relationship.
For a 'Yobi the Five Tailed Fox' fanfiction, we could add a bear cub. The bear cub is lost and Yobi takes it under her wing. This creates a heart - warming sub - plot. A snake charmer from a nearby village who has some knowledge of magic could also be a character. He could either be an ally or an enemy depending on the story's direction. And then there's the idea of a fairy. The fairy is drawn to Yobi's unique five - tailed form and offers to help Yobi enhance her powers in exchange for a favor. But the fairy has a mischievous side that could lead to some unexpected twists in the story.