Naruto's development would be a journey of self - discovery. As Orochimaru's apprentice, he would be exposed to different forms of power and knowledge. He might initially be disgusted by Orochimaru's methods but then realize that he can use some of it for good. His social skills would change too. He would be more adept at dealing with enemies and those with different motives. His sense of humor might even change, becoming darker to fit in with Orochimaru's crowd. But deep down, his core values of friendship and protecting the weak would still be there, just masked by his new persona as Orochimaru's apprentice.
They would develop in terms of their skills. Under Orochimaru, they would gain a lot of knowledge about chakra manipulation and forbidden jutsu. But with Naruto, they would learn about the power of bonds and friendship. This combination could lead to the development of new jutsu that combines both physical power and the strength of relationships. Also, they would grow in their understanding of right and wrong, as Naruto's moral compass would constantly be in conflict with Orochimaru's more amoral stance.
His character could develop in a darker direction. The torture and manipulation from Orochimaru's experiments could make him question his values. However, it could also strengthen his resolve to protect his friends and the village. He may start to see the world in a more complex way, understanding that there are greater evils out there. And his newfound powers from the experiments could give him a sense of responsibility that he didn't have before.
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.
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 view of the ninja world might change. Anko has a different perspective compared to some of Naruto's other mentors. She has seen the darker side of the ninja world, especially with her connection to Orochimaru. Naruto, as her apprentice, would be exposed to this side more, which could make him more cautious and also more understanding of those who have strayed from the right path.
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's character would likely be darker. Orochimaru is known for his unethical experiments and thirst for power. Naruto, under his tutelage, might be more focused on individual strength rather than the bonds he values in the original series. He could become more secretive and less trusting of others.
Naruto might become more cautious. Since he has faced Orochimaru before, he knows the kind of danger he represents. So he could start to analyze situations more carefully before jumping into action.
Naruto's character development in this fanfiction would be complex. He'd probably grow up with a sense of superiority due to Orochimaru's powerful teachings. But at the same time, he'd lack the warmth and compassion that came from his relationships in Konoha. He might be more self - centered, focused on his own power and survival. He may not have the same sense of justice as in the original Naruto, as Orochimaru's motives are not in line with the general good. And his relationship with his peers would be more of a power struggle. He might not form the same deep friendships, but rather see others as either tools or threats.
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.