One common theme is the struggle for identity. Since vampires are different from the normal Soul Reapers or humans in the Bleach world, they often struggle to find their place. For example, a vampire might question whether they belong to the dark side or can find a way to co - exist with the good guys.
The theme of redemption also pops up. Characters who have done wrong in their own series might find a chance to redeem themselves in the fanfiction world. For instance, a villain from 'Bleach' could end up in the 'The Vampire Diaries' universe and try to change their ways by helping the good guys against the vampires or other threats in that world.
One common theme is power. Yamamoto is extremely powerful, and fanfics often explore the extent of his power, like how he can handle really tough enemies. Another theme is leadership. As the head of the Gotei 13, his leadership style and decisions are often the focus. For example, how he manages to keep the Soul Society in order.
One common theme is the exploration of the power of Hyourinmaru. Writers often delve into how the sword's abilities can be developed or used in new and creative ways. Another theme is the relationship between the wielder of Hyourinmaru, usually Toshiro Hitsugaya, and the sword itself. It could be about their bond growing stronger or facing challenges that test their connection.
One common theme is her relationship with other Sternritter members. Since she is a part of that group in 'Bleach', many fanfics explore how she interacts with them, whether it's loyalty, rivalry, or friendship.
A common theme is also the exploration of Ichigo's character growth in the context of these two different universes. In Bleach, he has his own journey of self - discovery and power development. When combined with the world of Rosario Vampire, there are new challenges and opportunities for him to grow. Writers often delve into how he adapts to the new situations, makes new friends or enemies, and how his moral compass might be affected by the different rules and cultures in the Rosario Vampire world while still maintaining his core values from Bleach.
One common theme could be power - level comparisons. Since Naruto and Bleach both have complex power systems, a fanfic might explore how Yamamoto's power from Bleach compares to the various powers in the Naruto universe.
One common theme is legacy. It's about how the new generation lives up to or breaks away from the legacies of their parents or predecessors. Another is growth, as the new characters develop their powers and personalities.
One of the themes is the struggle for acceptance. The fem OC is often different from the normal characters in the Bleach universe, so she has to fight to be accepted. Another theme is the exploration of the different realms in Bleach. The fem OC might travel between the Human World, Soul Society, and Hueco Mundo, and each place has its own challenges and mysteries that she has to face.
One common theme is Kazui's discovery of his powers. Since he is a new and somewhat mysterious character, many fanfics explore how he comes to understand and control his abilities, much like Ichigo did in the original 'Bleach' story.
Power combination is a common theme. Writers like to explore how the powers from Naruto, like ninjutsu, and those from Bleach, like zanpakuto abilities, can be combined. For example, a character might use chakra to enhance their zanpakuto skills.