What could be the plot of a Highschool DxD fanfiction where Issei and Rias get married?

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.

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.

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 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.

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 possibility is that they would face many challenges together. Since they are from different worlds in a sense, they'd have to deal with the politics of the devil world. Their relationship might be a symbol of change, leading to more cooperation between devils and humans. Also, their engagement could bring about a new era of peace in the 'Highschool DxD' universe.

In some fanfiction scenarios, Rias might be involved in a political intrigue within the 'Highschool DxD' world that Issei doesn't understand or approve of. Her actions during these events, such as making alliances with characters Issei distrusts, could lead to his dislike. Also, if she were to accidentally expose Issei to danger due to her own miscalculations in these political games, that would surely sour their relationship.

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.

You can try fanfiction websites like Fanfiction.net or Archive of Our Own. Just search for 'Highschool DxD Issei x Rias' on their search bars, and you'll likely find a good number of fanfictions related to them.