There could be a plot where Koneko is transported to an alternate dimension that combines the Naruto and Highschool DxD worlds in a very strange way. In this new dimension, she has to find a way back home while also facing new threats. For instance, there could be a new type of enemy that has the abilities of both ninjas and devils. She might also have to deal with cultural clashes between the two groups of characters she meets. Along the way, she could learn new skills and powers that are a blend of the two universes, and this could lead to her character growth and development as she overcomes various challenges in this strange new world.
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.
Well, a really interesting plot could be that Koneko gets involved in a tournament where both Naruto - style combat and Highschool DxD - style battles are allowed. She has to use her unique skills and knowledge from both universes to win. Also, a plot where Koneko discovers a hidden connection between the two worlds, like a secret organization that has been manipulating events in both Naruto and Highschool DxD universes, and she has to stop them. This would involve her teaming up with characters from both series and using her wits and powers.
One idea could be Koneko's journey to master a new power. Maybe she discovers an ancient technique related to her Nekomata heritage and has to train hard to control it. Another plot could involve her forming an unlikely alliance with a character from an opposing faction to solve a mystery in the school that affects both sides.
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.
One plot idea could be that the OC is a new transfer student at the school and has a special power that Koneko is initially suspicious of. As they are paired up for a school project, they start to understand each other better. The OC could be from a different supernatural group, and through their interactions, they help bridge the gap between their respective groups in the Highschool DxD universe.
Well, a plot could revolve around a mystery that involves both worlds. Maybe there is an ancient artifact that has the power to disrupt the balance between the Naruto universe and the Highschool DxD universe. Characters from both sides have to work together to find and protect this artifact. This would lead to a lot of character development as they learn about each other's cultures and values while on this quest.
One interesting plot could be about Koneko forming a stronger bond with the main character outside of the regular events in the original series. For example, they might go on a quest together to discover a hidden power within Koneko.
One idea could be that Naruto somehow gets transported to the High School DxD world and has to deal with the devils and angels there while still having his ninja skills. He might use his shadow clone jutsu in unique ways during battles in the new world.
One idea could be a crossover where Naruto characters end up in the Highschool DxD world and have to adapt to the different rules regarding magic and devils. For example, Naruto could use his chakra in unique ways against the devils' powers.
Well, a cool plot could involve a character from Naruto getting transferred to the Highschool DxD universe. They could bring some ninja techniques and wisdom which would be really interesting in the context of the more modern and somewhat chaotic world of Highschool DxD. Or perhaps there's a mystery that only the skills of Naruto characters can solve in the Highschool DxD setting, like a strange demonic phenomenon that has ninja - like stealth and secrecy.
A plot could be that the Akatsuki from Naruto are after a powerful artifact in the Highschool DxD world that is related to Lucifer. This would bring the two universes into conflict as the devils and other supernatural beings in Highschool DxD would not want the Akatsuki to get their hands on it. Naruto characters like Sasuke or Kakashi could be pitted against the devils like Issei or Rias. And Lucifer could be in the middle, either trying to stop the Akatsuki for his own reasons or using them to gain more power in his own world.
Another idea is that a powerful artifact has been stolen and its pieces are scattered across the three worlds. Naruto, Gabriel, and the Highschool DxD characters must team up to find all the pieces. As they search, they encounter different challenges in each world. In Naruto's world, they face ninja clans who want the artifact for their own power. In Gabriel's world, they must deal with angelic politics. And in the Highschool DxD world, they have to fight off demons who also want the artifact.