Growth is a prevalent theme. Fanfictions usually show how Naruto and Sasuke grow both as individuals and in their relationship. They start as two little kids with their own issues - Naruto with his loneliness and being an outcast, Sasuke with his family tragedy. As they interact, they learn from each other and become better. Also, the theme of family is often explored. Naruto's longing for a family and Sasuke's complex relationship with his own family are important aspects that are developed in these fanfictions. For example, in some fanfictions, Sasuke tries to share his family memories with Naruto, which helps Naruto understand him better.
One common theme is friendship. Despite their differences, they are often shown forming a unique bond even as children. Another theme is rivalry, which is a big part of their relationship in the original series and is carried over in fanfiction. They compete in various ways, like in ninja skills.
One of the main themes is the contrast between their personalities. Naruto is outgoing and Sasuke is more reserved, and how they deal with this. Also, the theme of loyalty often comes up, loyalty to each other and to their village. And there's the theme of acceptance, Sasuke accepting Naruto as a friend and Naruto accepting Sasuke's past traumas.
One common theme is Sasuke's growth. Writers often explore how he developed his skills and mindset as a child. Another theme is his relationships, like his friendship or rivalry with other characters when he was young.
One common theme is redemption. Sasuke has done a lot of things that some might consider wrong, and in many fanfictions, Naruto is the key to his redemption. Another theme is friendship. Their bond is often explored in different ways, like how they support each other in tough times. Also, the idea of power and how they use it together or against each other can be a theme.
Another theme is redemption. Sasuke's actions in the original story make his path to redemption a popular topic. Fanfictions might show how Naruto helps him find his way back to the good side. For example, in some stories, Sasuke has to make amends for his past deeds with Naruto's support.
One common theme is brotherly love. Itachi's love for Sasuke despite the hardships they face is often explored. For example, in many fanfictions, Itachi sacrifices a lot to protect Sasuke.
The theme of growth is very common. All three characters - Naruto (the adopter), Naruto (the younger self) and Sasuke - experience personal growth. They learn from each other, share their skills and knowledge. For example, Naruto might teach Sasuke some new jutsu, while the younger Naruto learns about the importance of friendship from Sasuke. This mutual growth is what makes these fanfictions interesting.
The theme of sacrifice also shows up a lot. Both Naruto and Sasuke are characters who are willing to sacrifice for the other in the original story, and this is often explored further in fanfiction. Writers might create scenarios where one has to make a big sacrifice for the other, which then tests and deepens their relationship.
Power and its limits is another one. In these fanfictions, we see them constantly testing their powers. Naruto might be trying to master new jutsus without losing himself. Sasuke could be grappling with the power of his Sharingan and how far he should go with it. Kakashi, with his Sharingan and his own unique skills, also serves as an example of someone who has learned to control and use his power effectively within certain limits.
Another theme is the way she is perceived in the ninja world. As a girl, she may face different expectations and prejudices. Some fanfictions explore how she overcomes these and still manages to be a strong ninja. In many of these stories, she has to prove herself more because of her gender.
One common theme is the resolution of their complex relationship. The kiss often symbolizes a new start or a deep understanding between them.