The unique combination of the Highschool DxD universe and the Neko element. In the Highschool DxD world, there are already so many supernatural elements, and adding the Neko aspect brings in a new level of cuteness and mystery. It can lead to interesting character interactions, like how the regular characters in Highschool DxD would react to the Neko characters.
An OC (Original Character) in a Highschool DxD fanfiction having the Rinnegan could be an extremely powerful and unique addition. The Rinnegan, from the Naruto universe, brings a whole set of abilities like the Six Paths powers. In the context of Highschool DxD, this OC could use these powers in various ways. For example, the ability to see chakra could be translated into seeing the magical energy in the DxD world. They could use the gravitational powers of the Rinnegan to manipulate the environment during battles against devils, angels, or fallen angels. It would make for a very interesting and overpowered character in the Highschool DxD fanfiction setting.
The OC, as the Son of Sparda, could fit in by being a new and powerful entity. He might be initially seen as an outsider, but his powers would quickly draw attention. He could become involved in the power struggles between the different factions in Highschool DxD. For example, the devils might try to recruit him, while the angels might be wary of his presence. His unique abilities would also make him a valuable ally or a fearsome opponent. And in the high school setting, he could be a bit of an enigma to the other students, both human and supernatural.
You can try fanfiction websites like FanFiction.net or Archive of Our Own. They usually have a large collection of Highschool DxD Neko fanfictions. Just use the search function on these sites and type in 'Highschool DxD Neko' to get relevant results.
One great fanfiction could be where the OC has a unique power that Akeno is initially intrigued by. For example, the OC might have the ability to control light in a different way than the devils in the Highschool DxD universe. This could lead to a series of adventures where Akeno and the OC team up to face various challenges. They could start off as just acquaintances but gradually develop a deeper bond as they fight side by side.
One possible aspect could be the unique abilities that Eve might possess in her reincarnated form. In Highschool DxD fanfiction, new characters often bring fresh powers. For example, Eve could have a special power related to light or healing, which would make her a valuable asset to the group. This could also lead to interesting storylines where she has to learn to control her powers while also dealing with the typical Highschool DxD chaos of devils, angels, and fallen angels.
To write a Highschool DxD OC Angel fanfiction, start with a strong concept for your angel. Are they a high - ranking angel with a lot of power or a newbie just learning the ropes? Next, think about their relationships. Who will they be friends with? Enemies? You can also add some unique abilities to your OC, like the ability to heal any wound or the power to manipulate light in a special way. As you write, keep the tone and style of the original series in mind to make it feel like it belongs in the Highschool DxD world.
One great Highschool DxD OC Angel fanfiction is 'The Angel's Ascent'. It has an interesting plot where the OC angel has to navigate the complex world of the DxD universe while hiding her true powers. It's full of action and some great character development.
To write a Highschool DxD OC Peerage Fanfiction, start with a strong concept for your OC. Are they a reincarnated hero? A new type of devil? Once you have that, build the peerage around them. Each member should have their own distinct personality and role. For the plot, you can draw inspiration from the original series like the Rating Games. But also add your own twists. For example, what if there was a new type of Rating Game that only OC peerages could participate in? Write detailed descriptions of the battles, the character's growth, and the evolving relationships within the peerage.
Maybe the OC is a descendant of an ancient race that was once closely associated with the power of Divine Dividing. They come to the high school to find out more about their heritage and end up getting involved in the power struggles between the different factions in the DxD world. This could involve making alliances and enemies along the way.