The OC's backstory as a gamer is crucial. Maybe they were a bullied gamer in the human world but in the Highschool DxD world, they find a new sense of purpose and power. Their journey from being an underdog gamer to a powerful figure in the DxD world can be very memorable. Also, give them some quirks like always quoting game lines at inappropriate times which adds humor and memorability.
One possible plot could be that the OC gamer, being a huge fan of the Highschool DxD world in his own gaming realm, somehow gets transported into the world. He then meets Raynare. Maybe at first, Raynare tries to use him for her own purposes as she usually does. But as the story progresses, the gamer's unique skills from his gaming world start to change her perception of him. For example, he might be able to analyze situations like he does in games and come up with strategies that no one in the Highschool DxD world has thought of. This could lead to an interesting dynamic between them, with Raynare slowly starting to trust the gamer and they end up on some kind of adventure together.
Some 'oc the gamer highschool dxd fanfiction' focus on the relationships the OC forms. Since they come from a 'gamer' background, they might approach relationships in a different way compared to the regular characters in High School DxD. This can lead to some really interesting character dynamics and story developments.
A unique and well - developed OC. If the original character has an interesting backstory, personality, and goals within the world of Highschool DxD, it can make the fanfic engaging. For example, if the Gamer OC has a special power or ability that is different from the existing characters in the series.
One idea could be an OC who is a gamer and discovers a hidden power within the Highschool DxD universe while playing a virtual reality game related to it. This power could be something unique like the ability to control shadows in the DxD world.
Another good place is Reddit. There are specific subreddits dedicated to Highschool DxD fanfiction. You can post a request asking for OP OC gamer fanfictions in that community. People there are often very helpful and can point you in the right direction. Some might even recommend their own favorites or works in progress.
Unique character design. If the original character (OC) has a distinct personality and backstory that fits well within the Highschool DxD universe, it can make the fanfiction stand out. For example, an OC gamer who has a special power related to gaming that also has an impact on the DxD world in an unexpected way.
The OC gamer could fit in by bringing a fresh perspective. For example, he might introduce new technologies or ways of thinking based on his gaming experiences. With Raynare, he could start by trying to understand her motives. Maybe he offers her a deal where she helps him navigate the world in exchange for something she wants. This way, he can gradually build a relationship with her and find his place in the world.
A Highschool DxD SI Gamer OC fanfiction can stand out by having a really unique SI OC design. For example, if the character has a very distinct backstory related to their gaming experience, like they were a pro - gamer in a previous life and now they have to use those skills in the Highschool DxD world. This makes the character more interesting and different from the regular characters in the series.
The adaptation of gaming mechanics into the Highschool DxD world is also really cool. The SI OC might introduce things like RPG - style leveling systems for the characters in the story. So instead of just the normal power - ups in the original series, characters could gain experience points and level up, unlocking new skills and abilities, which would change the power dynamics and the overall flow of the story.