Yes, there are likely many. While there are some fanfictions that might include inappropriate or 'lemon' content, a large number of fanfic authors focus on creating clean, plot - driven stories. You can search on fanfiction platforms and filter by appropriate ratings to find ones that are more in line with a general - audience reading.
In a fanfiction, Issei and Koneko could be paired for a school project. At first, they struggle to work together because of their different personalities. Issei is more outgoing and impulsive, while Koneko is quiet and reserved. But as they dig deeper into the project, they start to understand each other better and develop feelings for one another.
Definitely not. 'Highschool DxD' is a popular franchise, and creating fanfiction with such inappropriate content can not only damage the reputation of the original work but also make readers uncomfortable. Fan works should promote positive values rather than this kind of unseemly content.
Adventure and battle themes are quite common too. Koneko is a part of the Highschool DxD world which is full of supernatural battles and adventures. Fanfictions might take her on new quests, or have her face stronger enemies, all while she tries to uphold her values and protect those she cares about. This can make for some really exciting and action - packed stories.
One plot idea could be Koneko adjusting to the high school life which is a mix of Naruto and Highschool DxD elements. For example, she might have to deal with different types of jutsus in the school setting as well as the devilish powers from Highschool DxD. Another could be her forming an unexpected friendship with a Naruto character, like Naruto himself, and they learn from each other's powers and cultures.
I really like the fanfic 'Koneko's Heart for Issei'. In this one, it delves deep into Koneko's emotions towards Issei. It starts with her being a bit reserved but as the story progresses, her true feelings start to surface. Another interesting fanfic is 'Issei and Koneko: United'. This fanfic shows how they work together to face challenges in the Highschool DxD world, and their relationship blossoms as they rely on each other.
A plot could involve Issei and Koneko getting trapped in an alternate dimension. In this dimension, they have to find a way back home while also dealing with the strange creatures and rules there. This forces them to rely on each other more than ever and could spark a romantic relationship as they fight for survival.
You can start by looking on fanfiction websites like FanFiction.net or Archive of Our Own. Just search for 'Highschool DxD Koneko' in their search bars, and you'll get a list of relevant fanfictions.
Many of these fanfics focus on the relationship growth between Koneko and Issei. They often start with a basic friendship or acquaintance and develop into something more romantic. For example, in some fanfics, their shared experiences in battles or school events bring them closer.
One idea could be that Naruto is somehow transported to the world of Highschool DxD. He could use his ninja skills and chakra in the new world, maybe even teach some of the characters there a thing or two about combat. For example, he could show Issei how to better control his power using chakra control techniques.