One great fanfiction idea could be that Issei discovers a new power within himself that is directly linked to Rias's heritage. Maybe he can tap into an ancient magic that only works in harmony with Rias's own powers. As they train together to master this new ability, their relationship deepens beyond just the typical master - servant bond in the Highschool DxD world.
A popular fanfiction is 'Issei and Rias: United Front'. It portrays them as a powerful duo against their enemies. The author does an amazing job of writing their interactions, making it seem very natural. The story also has some great plot twists that keep readers engaged. You can find these fanfictions on various fanfiction websites. Just search for 'Highschool DxD Issei x Rias fanfiction' and you'll get a whole list to choose from.
One possible fanfiction could involve a grand wedding ceremony. Issei, being the determined and passionate character he is, would make sure every detail is perfect for Rias. They might have a wedding that combines the elements of the devil world and the human world they both cherish. Friends from both sides would come together to celebrate their union. The story could also include some humorous moments, like Issei trying to learn the complex devil wedding traditions and getting things a bit wrong at first.
Power - up themes are also quite common. Issei often gets new powers or abilities, and Rias may play a role in that. For example, in some fanfictions, Rias helps Issei to master a new form of his Sacred Gear. This not only strengthens Issei but also deepens their bond as they train together. Another aspect is the exploration of the supernatural world in the context of their relationship. Since Highschool DxD has a rich supernatural setting, fanfictions may expand on this, like how Issei and Rias face new threats from the underworld or other dimensions together, which further cements their relationship and showcases their individual growth.
One idea could be that Issei leaves Rias because he realizes he has different goals in the supernatural world. He might want to focus on helping the weaker devils rather than being part of Rias's peerage. So he sets out on his own journey, making new allies and facing new challenges.
There's a fanfic called 'Rias and Issei: A New Adventure'. In this one, they go on a journey together that tests their relationship. The author does a wonderful job of portraying their feelings for each other and the challenges they face as a couple in the world of Highschool DxD.
One idea could be a story where Issei and Rias have to go on a special mission together in a parallel dimension. In this dimension, they lose their powers and have to rely on their wits and the bond they've developed. They face challenges that test their relationship and force them to understand each other on a deeper level.
Another common theme is the exploration of the different arcs from the series but with a focus on Issei and Rias. This could include their adventures in the Underworld, dealing with rival devil groups, or facing new threats together. Fanfictions may expand on these storylines while highlighting their relationship.
Well, a fanfiction could focus on their daily lives outside of the battles. For example, Rias and Issei could have a cooking competition with their friends from the Occult Research Club. It would be a fun and light - hearted way to show their relationship and how they interact with the other characters in a non - combat setting.
A Rias and Issei wedding fanfiction could be full of grandeur. There would be various characters from the Highschool DxD universe in attendance. The wedding might take place in a magnificent location, perhaps a grand cathedral-like place in the Underworld. Rias would look stunning in a traditional yet unique wedding dress, and Issei would be in a sharp suit. Their friends would give heartwarming speeches, and there would be a sense of celebration not just for the couple but for the unity of different factions in the story.