A recurring theme is self - discovery. Naruto, coming from his own world, has to adapt to the DxD world. In this process, he discovers new aspects of himself, his powers, and his place in this new universe. And of course, there are often action - packed scenes as Naruto uses his skills to fight against the various threats in the DxD world that endanger his new friends and potential love interests.
The harem aspect itself is a big theme. Naruto, being the main character, attracts the attention of multiple female characters from the DxD universe. This leads to themes of romance, jealousy, and relationship building. Also, the exploration of different cultures and mythologies from both Naruto and DxD is common. For example, the ninjutsu from Naruto and the devil and angel lore from DxD are often explored.
One common theme is the power struggle. Since both Naruto and DxD have complex power systems, in the fanfiction, Naruto often has to prove himself in the DxD world which has its own set of powerful beings. Another theme is friendship. Naruto is known for his ability to make friends, and in these crossovers, he forms new friendships in the DxD world.
Power - building is a common theme. The OC usually starts off with some sort of special ability or knowledge and uses it to gain more power in the Highschool DxD universe. This power - building often attracts the attention of various female characters, leading to the formation of the harem.
One common theme is relationship building. Naruto has to form bonds with both Cayuga and the harem members. Another theme is adventure. They often go on quests or face challenges together.
Common themes include the building of a unique family or group dynamic within the harem. Naruto and Kurotsuchi might be at the center of this, but the other members also contribute. Another theme is the protection of the harem. Naruto, being a strong character, often has to protect the harem members from various threats. And of course, the theme of personal growth is there. As the characters interact in the harem, they grow and change, especially Kurotsuchi who might have to adapt to being part of a harem and sharing Naruto with others.
The theme of acceptance is also prevalent. Naruto has to accept the feelings of the fox - like characters in the harem, and they in turn have to accept him with all his flaws and powers. Another common theme is power. Naruto's existing powers or new powers he gains through his connection with the foxes play a big role in how the relationships in the harem are formed and maintained. For example, his newfound abilities might attract the foxes more or help him protect them.
One common theme is the fish - out - of - water situation. Naruto, being from his own universe, has to adapt to the new crossovers and the different rules and cultures there while also dealing with his new - found harem. Another theme is the power - up. Often, as he interacts with the different characters in his harem from other universes, he gains new powers or abilities. And of course, the relationship building within the harem, with all the jealousy, love triangles, and friendship that come along.
One common theme could be the development of Naruto's relationships with Samui and other characters in the harem. It might involve how Naruto deals with multiple romantic interests.
One common theme is the development of relationships. Since it's a harem concept, there's the exploration of how Naruto relates to Hinata and the other characters in the harem. Another theme is often the protection of loved ones. Naruto, being a strong character, is usually depicted as protecting Hinata and the others. And of course, there's the theme of love triangles or more complex relationship dynamics within the harem.
Power - up is a common theme. As characters from Naruto and Bleach come together in the harem, they often gain new powers or enhance their existing ones through their interactions. For example, Naruto might learn some spiritual techniques from the Bleach characters.
Love triangles are a common theme. Since it's a harem concept, there are often situations where Naruto has to choose between Konan and other characters who have feelings for him. Another theme is power dynamics. Naruto is a very powerful character, and how his power affects his relationships within the harem, especially with Konan, is often explored.
A common theme is Naruto's growth in power. As he becomes stronger, it often serves as a magnet for characters to be part of his harem. For example, in many such fanfics, after a major power - up, new characters start to show interest in him.