A prevalent theme is sacrifice. Given the dangerous nature of Anbu missions, there are often situations where one of them has to make a sacrifice for the other or for the greater good of the village. This theme adds a lot of depth and drama to the fanfictions. It also shows the strength of their relationship as they are willing to put themselves in harm's way for each other.
One common theme is loyalty. In the ANBU, loyalty to the village is of utmost importance. Fanfictions often explore how Naruto and Kakashi uphold or struggle with this loyalty. For example, they might face a situation where their loyalty to each other conflicts with their loyalty to the village.
One common theme is power adaptation. Since Kakashi is from the ANBU, he has a certain set of skills. In crossovers, he has to adjust these skills to fit the new world he's in. For example, if he crosses into a world with magic, he might need to figure out how his ninja techniques work with the new magic system.
One common theme is mentorship. Kakashi is Naruto's teacher, and many fanfictions explore how this relationship develops over time. Another theme is friendship. As they spend more time together, their bond of friendship often becomes a central focus. Also, the theme of growth is prevalent. Naruto grows as a ninja and as a person with Kakashi's guidance.
One common theme is growth. Both characters grow in their relationship as they learn more about each other. For example, Naruto may grow in his understanding of Kakashi's past traumas, and Kakashi may grow in his admiration for Naruto's determination.
One common theme is the development of their relationship against the backdrop of the dangerous ANBU world. Another theme is their growth as individuals within the ANBU.
The theme of protection is very common. Naruto, as an Anbu, is highly skilled and uses his abilities to safeguard Sakura. There's also the theme of unrequited love at times. In some fanfictions, Sakura may not be aware of Naruto's feelings at first because of his secret Anbu life, and Naruto has to find a way to make her understand his love.
One common theme is the growth of their relationship. As they work together in the ANBU, they get to know each other better.
One common theme is redemption. Since Kakashi has a lot of regrets in his life, in time - travel fanfics, he often tries to make up for his past mistakes. For example, he might try to save his comrades who died in the original timeline.
One common theme is mentorship. Kakashi often plays a crucial role in guiding Naruto and Sasuke, which is explored in many fanfictions. Another theme is friendship. Despite their differences, the stories usually emphasize the strong bond between the three.
One common theme is friendship. Despite their differences, Naruto, Kakashi, and Sasuke come together and their friendship deepens. Another theme is growth. They often grow as individuals as they interact with each other in these fanfictions.