The story could develop in a dark direction. Naruto might start to learn Orochimaru's jutsus. His personality could become more cynical. He'd be cut off from his usual support system in Konoha.
In fanfiction, if Naruto joins Orochimaru, the story would first show Naruto's initial hesitation and then his slow descent into Orochimaru's world. He'd be exposed to Orochimaru's experiments and secrets. The story might then focus on how Naruto's friends react. They'd be shocked and would try to figure out what made Naruto take this step. Meanwhile, Orochimaru would use Naruto's power for his own purposes, perhaps in battles against other villages or in searching for more forbidden knowledge. As time goes on, Naruto might either fully embrace Orochimaru's ways or find a way to break free and return to his true self.
Naruto's character would likely become more conflicted. He has always been on the side of good, and joining Orochimaru, even if for a good reason, would put him in a morally gray area. His view of power might change as he is exposed to Orochimaru's unorthodox ways of obtaining it.
In some fanfictions, Orochimaru might develop a sense of loyalty towards Naruto. After being around Naruto for a while, he could see Naruto as someone worthy of his loyalty. This could lead to him being more open to working with the Hidden Leaf and helping Naruto in his various missions. He might even sacrifice his own interests to protect Naruto at times, which is a complete turnaround from his initial character.
His character might become more adaptable. Naruto is used to Konoha, but in Kumo, he has to deal with new rules and a different social structure. This could make him more flexible in his thinking. For example, he might learn to approach problems in a more Kumo - like way.
His character would likely become more conflicted. He has always been a positive and determined person, but being around Orochimaru would expose him to a lot of darkness. He might start to question his own beliefs and values. For example, he may become more ruthless in battle as he adopts some of Orochimaru's combat styles.
It could develop in a very complex way. Maybe at first, it's full of hostility as Orochimaru has his own dark motives. But as the story progresses, Naruto's positive influence might start to change Orochimaru's perspective a bit.
In many fanfictions, it starts with Naruto's curiosity about Orochimaru. Naruto, being the character who always wants to understand others, is drawn to Orochimaru's mystery. This initial interest then leads to more interactions, which gradually develop into a deeper bond. For example, in some stories, Naruto might try to save Orochimaru from his own dark path, which then causes Orochimaru to see Naruto in a new light.
Her character could develop in a way that she becomes more independent. In the fanfiction, away from the protection of her usual teammates, she has to fend for herself among Orochimaru's minions. This would force her to rely on her own strength and intelligence. Also, she might develop a darker side. Being around Orochimaru's evil influence, she could struggle with maintaining her positive outlook and might have moments where she is tempted by the power he offers without considering the consequences.
If Naruto were to join Orochimaru in fanfiction, it would be a huge deviation from the original story. Naruto's values of loyalty and friendship would be put to the test. He might start to see the world from Orochimaru's perspective, which is often self - serving. This could also mean that Naruto would be involved in Orochimaru's plans to gain immortality, perhaps even becoming a part of his body - swapping experiments in some extreme cases.
The story could start with Naruto finding Obito in a desolate place. Naruto would be curious and approach him. Then, they would exchange words, and Naruto would offer his help to Obito. As they interact more, they might face some small - scale battles together against rogue ninjas or other threats. This would build trust between them.
Naruto's character might develop a stronger sense of purpose. Saving Sasuke becomes more than just about their friendship; it could be about righting a wrong in the ninja world. His resolve to save Sasuke would make him train harder and become more strategic in his battles.