The OC in Orochimaru's body could also change the relationship between Orochimaru and his former students like Kabuto. Instead of using Kabuto as a tool, the OC might actually mentor him in a more positive way. This could lead to Kabuto having a different role in the story. He could potentially become an ally to the main characters much earlier, and his power could be used for good rather than being a pawn in Orochimaru's and later Tobi's plans.
The OC as Orochimaru could have a major impact on the Akatsuki. Maybe they would try to infiltrate the group and undermine their plans from the inside. Since Orochimaru was once part of the Akatsuki, the OC could use this position to gather information and prevent the Akatsuki from capturing the tailed beasts. This would change the entire course of the story as the Akatsuki's actions were a major driving force in the Naruto plot.
If an OC was reborn as Orochimaru, they might not attack Konoha in the same way. They could try to form an alliance instead, seeing the potential in working with the village rather than against it. This would change the whole dynamic of the early Naruto story, especially Sasuke's journey as he might not be so hell - bent on revenge against Konoha if Orochimaru wasn't an enemy.
The story would also change in terms of Naruto's relationships. His friends like Sasuke and Sakura would be very concerned and might try to stop him. This could lead to a rift between them. Naruto might gain new powers faster, but at a cost. He could start to lose his connection to his normal self and the Nine - Tails inside him might react negatively to the experiment.
Naruto would likely be more cunning. Since Orochimaru is known for his devious ways, Naruto might inherit some of that. He could be more calculating in battles rather than just relying on brute force. However, he would still have his core of kindness. So, it would be an interesting mix of Orochimaru's slyness and Naruto's big - heartedness.
Naruto's morality could be somewhat skewed. Orochimaru has a very different view on right and wrong compared to Naruto. So, Naruto might start to question some of his previous beliefs. For example, he might be more willing to use dangerous or forbidden jutsus if it means achieving his goals. He'd also probably be more distrustful of others, as Orochimaru always has ulterior motives. This would be a big change from the Naruto who was always so quick to trust and befriend people.
Naruto would likely become more secretive. Since Orochimaru is a very private and often devious character, Naruto might pick up some of those traits. He would probably keep things from his friends more often.
Naruto would likely become more secretive. Since Orochimaru's training methods are often not in line with Konoha's values, Naruto would have to hide what he's learning. He might also become more distrustful of others as Orochimaru could instill in him the idea that everyone is out to get him for his newfound power.
On the other hand, their relationship could also grow stronger. They would be relying on each other more in this new and dangerous situation. Naruto would be even more protective of Hinata, and Hinata would be a source of comfort for Naruto. They would have to communicate and trust each other more deeply to survive in Orochimaru's lair.
In fanfiction, Naruto joining Orochimaru could make him a more complex character. He'd be exposed to Orochimaru's unethical practices, which could make him question the ninja world's values. He might develop a darker side, but also a deeper understanding of the gray areas. Sasuke would experience a transformation too. His relationship with Orochimaru would be a strange mix of mentorship and power struggle. He could become more ruthless, but also more calculating. His interactions with Naruto in this new setting would be full of tension and moral dilemmas.
He would become more cynical. Orochimaru's influence would make Naruto question the values he once held dear in the village. His appearance might also change, with a darker look in his eyes and a more menacing aura.
Naruto's character would change a great deal. He would be exposed to Orochimaru's world of experimentation and dark magic. This might make him more cynical about the ninja world. Also, he would have to adapt to Orochimaru's strict and often cruel training methods. As a result, he could become more introverted and less trusting of others. His once open - hearted nature might be replaced with a more guarded one.
He'd be more cynical. Orochimaru's ways would make Naruto question the goodness in people.