One way their characters are developed differently in fanfiction is through their parenting styles. In the original series, since they die early, we don't really see them as parents. But in fanfiction, we can see different approaches. Minato could be the strict yet loving father, teaching Naruto advanced ninjutsu from a young age. Kushina could be the nurturing mother, always making sure Naruto is emotionally okay. Additionally, their characters can be developed in relation to the political situation of the village. They could be involved in secret political maneuvers to protect the village and Naruto's future as a potential great ninja.
In the original series, Naruto is mainly focused on becoming Hokage and getting Sasuke back. In the fanfiction, as Anbu Naruto, he might be more secretive and have a darker side. He could be more cynical about the village's politics. Female Sasuke, on the other hand, may be more independent than in the original. She could be more involved in political matters in the village rather than just seeking revenge. For example, she might use her skills to try and reform the ninja system.
In some fanfictions, Naruto, Hinata and Sasuke's relationships can be drastically different. Naruto and Hinata could start a relationship based on a shared interest in a new form of ninjutsu that Hinata discovers. This brings them closer together in a way that wasn't shown in the original. Sasuke, on the other hand, could be forced to live with Naruto and Hinata for a period of time due to some village regulations. During this time, he sees their relationship up close and it makes him re - evaluate his own ideas about relationships and loyalty. He might start to see the value in what Naruto and Hinata have and become more protective of them.
Sasuke in fanfiction could be developed with more vulnerability. In the original series, he is often seen as stoic and brooding. But in fanfiction set in the ANBU world, he might show his fears and doubts more as he has to deal with the high - stakes and secrecy of ANBU missions. Sakura could be more assertive. In the original, she sometimes seems to be in Sasuke's shadow. Here, she could be an equal or even a leader in ANBU operations. The ANBU environment forces both of them to grow in new ways.
In fanfiction, their characters can be developed in various ways. For example, Kallen might be more open about her feelings towards Lelouch earlier than in the original series. Maybe she directly confronts him about her admiration and loyalty, which could lead to different relationship dynamics.
Well, in some fanfictions, Harry's relationship with werewolves could be explored in a much deeper way. He might develop a more empathetic side towards them, especially if he meets a werewolf who is not as bloodthirsty as the ones he has encountered before. Hermione could be developed to be more of a risk - taker. When it comes to werewolves, she might be willing to put herself in more dangerous situations to study them or help them, which is different from her usually cautious self in the original series.
Naruto could be given a more complex personality in the modern fanfiction. He might be more introverted at first, having to deal with the loss of his father in a modern way (like through memories in a digital photo album). Kushina, on the other hand, could be shown as having a secret past that is slowly revealed through modern - day detective work by Naruto and his friends, which would be a big departure from her straightforward backstory in the original.
Dark Naruto could be developed to have a different set of ninja skills. He might learn some forbidden jutsu on his own in his journey to the dark side, which gives him an edge over others. In terms of Fem Sasuke, she could be more in tune with her feminine side. Instead of just being cold and brooding like the original Sasuke, she could use her charm and intelligence to get what she wants. For instance, when dealing with enemies, she might use her wits to outsmart them rather than always relying on brute force. Also, Dark Naruto could have a more philosophical side, constantly questioning the nature of power and the ninja world, which is different from the more impulsive original Naruto.
Some characters might develop new skills. For instance, Hermione could learn a type of magic from another universe that makes her even more powerful. This would change her role in the story and how others interact with her.
Uhura's character could be developed to be more assertive in her relationship with Spock. In fanfiction, she might take the lead in certain situations, like when it comes to making decisions about their future together. This is different from the original series where she was more in a supporting role in their relationship.
In fanfiction, Roxas might be developed to have more complex emotions about his existence. For example, he could struggle more with his identity as a Nobody and his connection to Sora in ways not fully explored in the game. Xion, on the other hand, could be given more backstory about her creation. Maybe the fanfiction delves deeper into the experiments that led to her existence.