One common theme is power - up. Since Naruto is already a powerful character in his own right, and the DxD world has its own power system, often in these fanfictions Naruto gets new powers or finds ways to combine his existing powers with DxD elements. For example, his chakra could be combined with the magic in DxD.
One interesting 'Naruto Phenex DxD Fanfiction' could be 'Naruto in the DxD World'. It combines the elements of Naruto's skills and the unique world of DxD quite well. The story often has Naruto using his ninja abilities in the DxD universe, which makes for some exciting battles and interactions with the DxD characters.
One interesting crossover could be the sharing of power concepts. In Highschool DxD, the Phenex family has unique powers like immortality and fire abilities. In Naruto, there are also various powerful jutsus. A crossover could explore a character from Naruto learning about the Phenex powers and incorporating them into his own fighting style. For example, Sasuke might be intrigued by the Phenex's fire powers and try to combine it with his own fire - based jutsus like the Great Fireball Technique to create a more powerful attack.
One great 'godlike naruto phenex highschool dxd fanfiction' could be 'Naruto in the World of High School DxD'. It combines the unique powers of Naruto in the setting of the High School DxD universe. The character interactions are really interesting as Naruto's brash and determined nature clashes and also meshes with the different personalities in the DxD world.
Often, the characters' personalities play a big role. Naruto's determination could inspire some of the more laid - back characters in Highschool DxD. And the devils' more sly and cunning nature might teach some of the Naruto characters new ways of approaching problems. There could be a fanfiction where Naruto teams up with Issei to take on a common enemy. They would combine their combat styles, with Naruto using his shadow clones and Issei his boosted gear, creating a really cool fight sequence.
Another common pairing is Sasuke and Akeno. Sasuke's brooding and powerful nature might attract Akeno, who is also quite powerful and has a bit of a mysterious side herself. They could bond over their shared power levels and a mutual understanding of what it means to be different from the norm in their respective worlds.
Well, Naruto is obviously one of the main characters. He brings his ninja skills and his own unique personality to the High School DxD world. Then there are the characters from High School DxD like Issei Hyodo. Issei is often involved in the story as Naruto's presence disrupts the normal power dynamics in the school and the devil world. Also, members of the Phenex family can be main characters depending on the specific plot of the fanfiction, as they are related to the Phenex aspect in the title.
The Phenex's ability of immortality could give Naruto an edge in battles. He could be more fearless in combat knowing that he has a sort of 'backup' in case things go wrong. And Naruto's chakra could potentially enhance the Phenex's fire abilities. For example, if a Phenex character were to use their fire with Naruto's chakra infusion, the fire could become more powerful and have unique properties.
The main themes can vary widely. But often there is the theme of adaptation. Since she is in the High School DxD world, she has to adapt to different situations. Love is also a theme sometimes, whether it's romantic love or love for her comrades. And there's the theme of destiny, like what her true purpose is in this fictional universe which is full of magic, power struggles and various factions.
The popularity of 'oc phenex dxd fanfiction' might be due to the fact that it allows for a lot of creativity. People can create their own unique characters within the established DxD universe, like the Phenex. It gives fans a chance to explore different storylines that the original might not have covered.