Another plot twist could be that Obito is secretly training Naruto to fight against an even greater enemy that no one else is aware of yet. This enemy could be an ancient force that is about to awaken, and Obito believes Naruto is the only one who can stop it. So, he's training Naruto in unique and unorthodox ways that seem strange to others at first.
Naruto's fighting style would likely become more stealth - oriented. Since Obito is known for his ability to move undetected, he might teach Naruto some techniques to blend into the shadows and surprise his opponents. For example, Naruto could learn to use the environment to his advantage in a more subtle way, rather than his usual straightforward attacks.
A great Naruto Obito fanfiction could explore his relationship with Rin in more depth. Maybe it's a story where Obito has a chance to save Rin from dying, and how that would change his path. It could also show how his relationship with Naruto might be different as a result.
Well, Naruto would probably gain some really unique magical abilities. Fairy Tail mages are known for their diverse magic, and Naruto could combine his chakra skills with something like Fire Magic or Celestial Magic. He might become even more powerful in combat, with new ways to attack and defend.
Naruto would gain better combat awareness. Kurama's experience in battles can be passed on to Naruto. He'll be able to read his opponents better, know when to attack and when to defend. This will make him a more formidable opponent in combat situations.
The impact would be huge. Naruto has always been a symbol of hope and friendship in the Naruto world. If he becomes like Obito, that symbol would be shattered. His friends and allies would be in shock and confusion. Konoha would likely be thrown into chaos as they try to figure out what happened to Naruto and how to deal with his new, potentially dangerous mindset.
In a 'naruto joins obito fanfic', it could start with Naruto being transported to a parallel dimension where Obito has already started his own ninja village. Naruto, seeing the potential in Obito's ideas but also the flaws, decides to join him. He helps Obito to correct his path. For example, Naruto could teach the ninjas in Obito's village about the importance of hope and not giving in to hatred. They could then work together to build a village that is a model for the rest of the ninja world, based on both Obito's and Naruto's ideals.
In this kind of fanfiction, Naruto might first try to understand Obito's motives. He could see the pain and loneliness that drove Obito to his dark path. Maybe Naruto would try to convince Obito to give up his evil plans and return to the side of good. They could form an unlikely alliance against a common enemy, like Madara or Kaguya. Naruto's positive attitude and Obito's powerful abilities would make a very interesting combination.
A very prevalent theme is the exploration of the characters' inner turmoil. Both Naruto and Obito have had difficult lives. In yaoi fanfiction, this inner pain is often used as a basis for their connection. They understand each other's pain on a deeper level, which leads to a closer relationship. Also, the theme of breaking taboos is there. In the Naruto universe, same - sex relationships might be considered a bit out of the norm, so exploring this in fanfiction is a common theme.
One possible plot could be that Naruto and Obito are forced to merge due to some dark jutsu gone wrong. Their combined form might initially struggle with two different sets of memories and personalities. Naruto's positive and determined nature could start to influence Obito's more cynical side. Eventually, they might use their combined powers to fight a new, powerful enemy that neither could have defeated alone.