Often, they emphasize the loyalty between Naruto and his ninken. For example, in many such fanfictions, the ninken will stand by Naruto no matter how difficult the situation is.
One common theme is loyalty. The Ninken are always shown to be extremely loyal to Naruto, standing by his side through thick and thin. For example, in many fanfictions, they'll fight to the death to protect him.
One great Naruto has a Ninken fanfiction is 'The Bond of Naruto and His Ninken' on FanFiction.net. It delves deep into how Naruto's relationship with his Ninken grows over time, showing their adventures together and how they support each other in battles.
One popular naruto has ninken fanfiction is 'The Bond of the Ninken Squad'. It focuses on the relationship between Naruto and his ninken, exploring their adventures together. Another one could be 'Ninken Training Days' which delves into how Naruto trains with his ninken to become stronger.
Maybe the fox ninken was once a normal ninken that was experimented on by some rogue ninja. Naruto stumbles upon it and through his kind heart and determination, he helps the ninken control its new fox - like powers. They then train together and the ninken becomes an important part of Naruto's team, using its speed and stealth to gather intelligence.
Maybe the Ninken is a special one with some sort of prophecy attached to it. Naruto gets the Ninken and at first doesn't understand its true significance. But as time goes on, he realizes that the Ninken is key to unlocking a new power within himself. The Ninken also has its own backstory that is slowly revealed as the story progresses, like it was once part of a great ninja's team and has been waiting for the right person to come along, which is Naruto.
His friends might be a bit jealous at first. For example, Sasuke could see the fox ninken as another sign of Naruto getting stronger. But eventually, they would come to accept it. Shikamaru might be intrigued by the strategic possibilities the ninken brings to their team. Choji could be excited to have a new 'team member' to share food with.
The Ninken could also have interactions with some of the village elders. They might be a bit cautious about this new addition to Naruto's entourage. But as the Ninken proves its loyalty to the village, they start to accept it. Naruto's relationship with the Ninken could also affect his interactions with the villagers. Some might be more afraid of Naruto now that he has this powerful animal by his side, while others might see it as a sign of Naruto's growing power and status in the village. And of course, there could be interactions with the various enemies Naruto faces. The Ninken could be a target because of its connection to Naruto, which would lead to some intense rescue and protection scenarios.
Yes, there are likely fanfictions out there where Naruto has a zanpakuto. Fanfiction writers often like to cross over different anime concepts. They might give Naruto a zanpakuto from the Bleach universe to explore new storylines and character developments. It can lead to really interesting scenarios where Naruto has to learn to use the zanpakuto's powers, which are quite different from the chakra - based abilities in Naruto's original world.
There could be such a fanfiction. The world of fan - created content is full of surprises. Writers might be inspired to give Naruto the power of Hamon for several reasons. It could be to create a more complex power system in the Naruto world, or perhaps to introduce a new type of threat that only Hamon can counter. Maybe they want to see how Naruto's friends and foes would react to this new ability. So, while I can't say for sure, it's very likely that it exists out there in the sea of fanfiction.