Minato might also be a prominent character. As their teacher, he can influence the way Obito and Kakashi interact. In some fan fictions, he could be the one to help them resolve their differences or provide some crucial information about their past that changes their current situation.
Some fanfictions might explore the emotional aspect of their fight. For example, how their past friendship affects the battle. Maybe Kakashi hesitates to strike a fatal blow because of their shared history.
In some fan fictions, there might be a plot where Obito has a change of heart before a major battle with Kakashi. He could start to question his motives and the path he has chosen, leading to a very intense and emotional confrontation with Kakashi that is more about ideology than pure combat.
You could also check out Naruto fanfiction groups on social media platforms like Facebook. There are often enthusiasts who share and discuss their favorite fanfictions. Just search for relevant groups, join them, and then look for fanfictions about Kakashi vs Obito.
Sasuke could be a rival. He's always been competitive with Naruto, and he might see Fuu as an obstacle in Naruto's path. Also, some of the more arrogant ninja from other villages, like those who look down on Naruto's boisterous nature and Fuu's different style of fighting, could be rivals.
In the fanfiction, their relationship could develop in a very passionate way. Since Naruto is a very emotional and energetic character, and Fuu has her own charm. When they decide to have a child, they would be super excited about the future. However, they would also face difficulties like any couple. There might be times when Naruto's duties as a ninja conflict with his family life, and Fuu would have to be understanding. And vice versa. Through these ups and downs, their love for each other and their child would keep their relationship strong.
Naruto would initially struggle with the formalities of a political marriage. But as he spends time with Fuu, he would start to adapt. His character would become more refined in terms of handling political matters. He would learn from Fuu's grace and intelligence. Fuu would also change. She might become more assertive, as she has Naruto by her side. She would be more involved in making decisions for the greater good of both villages. Their characters would grow together, with Naruto's boldness and Fuu's tact combining to create a strong leadership duo for their joined communities.
Naruto's personality would likely become more mature. The responsibility of being in an arranged marriage might make him think more about the future. He would still keep his positive and determined side, but now he has someone else to consider. Fuu's personality could soften. She might start to open up more and show her vulnerable side to Naruto. The marriage could be a catalyst for her to become more trusting and less guarded.
Naruto could be one of his allies. Naruto has this knack for seeing the good in people and would probably be willing to give Obito a chance to redeem himself. Also, Sakura, with her skills as a medic - ninja, could be an ally. She might help heal Obito if he was injured during the war and see the potential in him to be a force for good.