A simple plot could be that they compete in a school - wide tournament. Koneko's pride as a Nekoshou and Issei's determination to prove himself make for an interesting dynamic. They both face tough opponents and along the way, they offer each other advice and support, gradually becoming closer friends.
One great Issei and Koneko fanfiction is 'The Bond of Opposites'. It delves into their relationship in a really interesting way. It shows how Issei's brash nature and Koneko's quiet demeanor play off each other.
In a fanfiction, it could be that Koneko and Issei are chosen for a special mission by the Gremory group. They are initially hesitant to work together as they have different approaches. However, as the mission progresses, they start to complement each other's styles. Koneko's stealth and Issei's more upfront fighting style work in harmony to defeat the enemy and complete the mission, and in the process, their relationship grows.
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.
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.
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.
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.
Another characteristic is the contrast in their personalities. Issei is outgoing and sometimes a bit of a perv, while Koneko is shy and reserved. This contrast creates an interesting dynamic in fanfictions. It can lead to humorous situations as well as some really heart - warming moments where they understand each other better despite their differences.
Well, it could be about Issei using his singing as a new power or ability. Maybe his singing can charm the devils, angels, and fallen angels alike. He could perform in some sort of supernatural concert where his voice has magical effects on the audience, like making them more friendly towards each other despite their different factions.
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 plot could be that they decide to have a traditional wedding in the Underworld. All their friends and allies from the different factions in Highschool DxD come together. Koneko might be initially hesitant but then fully supports her sister Kuroka. Issei would be nervous but excited, and there could be some comical moments as he tries to follow all the wedding customs.