Sasuke is often a popular character in these fanfictions. He might play a role in helping Naruto against Madara or have his own motives during their battle. Kakashi can also be a prominent figure, perhaps using his Sharingan in a crucial moment to assist Naruto. Another popular character could be Hashirama, as his connection to Madara is a key part of the original story and can be further explored in fanfiction.
Another theme is redemption. Sometimes in these fanfics, Madara has a chance at redemption through his fight with Naruto. Naruto's belief in people's goodness can influence the outcome in such scenarios.
Sure. In fanfiction, the rules can be bent or rewritten. Maybe Naruto discovers a hidden bloodline connection that enables him to use Wood Style. It could be that he has a distant relation to the Senju clan that was previously unknown. This new ability would change the dynamics in battles and his relationships with other characters like Sasuke and Sakura, as he would have a whole new set of skills to bring to the table.
Perhaps an OC who was raised by a group of forest spirits. The spirits taught the OC how to use Wood Style as a means of protecting the forest. This OC would have a very different view of the world compared to normal ninjas. Their Wood Style would be more in tune with the natural balance, and they might be hesitant to use it for violent purposes, only doing so when the forest or its inhabitants are in great danger.
The Wood Style OC could be a rival to Naruto. Since Naruto has the power of the Nine - Tails, the OC with Wood Style could see Naruto as a threat to their own status as a powerful ninja. This would lead to intense battles and a begrudging respect as they learn more about each other's abilities and motives.
Yes, there are. The Naruto fanfiction community is vast and creative. Some writers like to explore the idea of Naruto having Wood Style, often by creating unique storylines that might involve him learning it in a different way than the original series, perhaps through some new form of training or a special encounter.
Naruto would probably win. He has an indomitable will and has always found ways to overcome powerful foes. His experience and the unique powers he might gain with the Rinnegan could give him an edge over Madara.
One interesting plotline could be Naruto discovers a new form that gives him an edge over Madara. For example, a form that allows him to nullify Madara's Sharingan abilities. Another could be Madara having a change of heart due to Naruto's unwavering belief in him. Maybe he starts to question his own motives for destruction.
One possibility in fanfiction is that Naruto gets some sort of power - up or transformation that allows him to use Wood Style. It could be related to the power of the Nine - Tails. Since the Nine - Tails has such a vast amount of chakra, it might interact with Naruto's own chakra in a way that enables him to perform Wood Style jutsu. Or perhaps he inherits some DNA from Hashirama Senju in a very far - fetched but interesting fanfic scenario.
It could also have implications for his relationships. His friends and allies might view him differently, perhaps with a new level of respect or even a bit of envy. On the other hand, his enemies would likely be more afraid of him. And in terms of the ninja world as a whole, it might disrupt the existing balance of power, as Naruto would be adding a new and powerful ability to his already impressive arsenal.