It could be that in the fanfiction, Naruto is under some sort of mind control when he kills Issei. This would add an interesting layer to the story as Naruto would have to deal with the consequences of his actions once he is free from the control.
Well, in such a fanfiction, the plot could be set up in many ways. Perhaps Issei's actions in the crossover world are misinterpreted by Naruto as a threat. Naruto, being a protector of his village and friends, would not hesitate to eliminate a perceived threat. On the other hand, it could also be a dark - themed fanfiction where Naruto is somehow corrupted or forced into killing Issei against his normal moral code.
In some fanfictions, it's possible for Naruto to be Issei's father. Fanfiction often takes creative liberties and can create some really out - there family relationships. However, in the original Naruto and High School DxD (where Issei is from) canons, there's no such connection.
In such a fanfiction, it could be that Issei is bashed because he represents a different kind of hero compared to what Naruto stands for. Naruto is all about self - sacrifice and believing in others no matter what, while Issei is more about his own desires and power - seeking in a way. So when these two worlds collide in the fanfic, Issei might be made to look bad in comparison. Maybe the story has Naruto characters like Sasuke or Kakashi giving Issei a hard time because they don't approve of his behavior.
Yes, there might be such fanfictions out there. The idea of crossing over two very different anime universes like Naruto and High School DxD (where Issei is from) and creating a family - like bond between the characters is an interesting concept that fanfiction writers might explore.
Issei might inherit Naruto's chakra. This would give him the ability to perform ninja techniques like the Shadow Clone Jutsu. He could create multiple clones of himself to confuse enemies or help with tasks. Also, he could potentially inherit Naruto's ability to sense negative emotions, which would be useful in detecting threats.
Yes, there might be such fanfictions out there. Fanfiction writers often come up with creative crossovers like this. You can try searching on popular fanfiction websites using relevant keywords like 'Naruto Issei older brother' to find them.
One possible scenario could be that Naruto, with his shadow clone jutsu, creates a diversion that leads to an accidental explosion involving Kiba and his ninken. As for Issei, perhaps in a crossover setting, Naruto's Rasengan clashes with one of Issei's attacks and causes an explosion. However, this would require a lot of creativity to blend the two very different universes in a believable way.
Well, one possible plot could be that Naruto discovers some ancient and powerful jutsu that allows him to reach across different dimensions or realms to revive Issei. Maybe Naruto is on a mission to save the world from a new threat and he realizes that Issei has some unique power or knowledge that can help. So he uses this jutsu, brings Issei back, and then they team up to face the common enemy.
Well, it would be really interesting. Naruto's skills and values would be transferred into Issei's world. He might bring his ninja way to deal with the supernatural threats in Issei's universe. Maybe he would use his shadow clone jutsu to confuse the devils and fallen angels, and his rasengan could be a powerful weapon against them.