One common theme is the exploration of immortality. Since Naruto is aging slowly, it often leads to thoughts about living forever and what that means in the context of the ninja world.
There's 'Slowly Aging Naruto' where the story focuses on how Naruto's slow aging affects his training. Since he ages slower, he has more time to perfect his jutsu and develop new skills. This fanfiction also delves into how his friends like Sasuke and Sakura react to his unique situation over time.
One common theme is redemption. Itachi has a complex past, and in these fanfictions, Sakura often becomes a part of his journey towards redemption. For example, she might see the good in him that others don't and help him come to terms with his actions.
One common theme is self - discovery. The characters are often thrown into a new world and have to figure out who they are and what they want in this new life. For example, in 'Ascendance of a Bookworm', the main character discovers her love for books anew in the isekai world.
One common theme is character relationships. For example, exploring the deepening friendship between Naruto and Sasuke, or Naruto's romantic relationships with characters like Hinata. Another theme is the expansion of the ninja world. Writers might create new villages, new ninja clans, or new jutsu. Also, the idea of alternate universes is popular, where the events in the original 'Naruto' series take a different turn.
One common theme is alternate universes. Writers often like to create scenarios where Naruto and his friends are in a different world altogether, like a modern - day setting or a fantasy world other than the ninja world. This allows for a fresh take on the characters.
One common theme is the passing of the torch. Older Naruto is often shown mentoring the younger generation, like how Kakashi mentored him. Another theme is dealing with the scars of past battles, both physical and mental.
One common theme is the exploration of their self - discovery. Since they are the same person in a sense, they can see different aspects of themselves. For example, one Naruto might be more confident while the other is more reserved, and they learn from each other.
Teamwork is also a big theme. Despite being the same person in essence, the two Narutos often have to learn to work together. This can be challenging as they may have different personalities due to their different experiences. For example, one Naruto might be more cautious while the other is more impulsive. And the theme of friendship also plays a role, as they are, in a way, their own best friends in these stories.
Another theme is self - discovery. As Naruto faces his dark side, he often learns more about his true nature, his powers, and his place in the ninja world. It's like a journey of self - exploration but with a dark and dangerous twist.
A lot of slow start anime fan fiction has the theme of school life. Given that the anime is set in a school environment, fan fictions often continue to tell stories within that setting. This could include things like school festivals, exams, and extracurricular activities. Also, the theme of self - discovery is quite common. The characters in the anime are on a journey of finding themselves, and fan fictions may take this concept further, perhaps by having the characters face different situations that force them to re - evaluate who they are.