I think Naruto himself would be really interesting. His never - give - up attitude and his ability to make friends easily could have a big impact in the Highschool DxD world. He could also learn a lot from the different power structures there. Plus, seeing him interact with the devils and angels would be really cool. He might try to convince them to use their powers for more positive things, like he did with some of the villains in his own world.
Vali Lucifer is often a very popular character. His cool and powerful demeanor makes him a favorite. In fanfiction, he can be the center of many stories, whether it's about his further power - ups or his complex relationships with other characters.
One interesting concept could be the exploration of new powers for the characters. In fanfiction, authors might give the members of the Khaos Brigade unique abilities that weren't fully explored in the original series. For example, they could develop a character's magic in a different direction, like making a spellcaster's powers more elemental - based.
One possible plot could be that the characters from Naruto and Highschool DxD somehow end up in the same universe as the Khaos Brigade. Maybe Naruto characters are sent to the Highschool DxD world to help fight against the Khaos Brigade's evil plans. They could bring their unique ninja skills, like Naruto's shadow clones or Sasuke's sharingan, and team up with the devils and other beings in the Highschool DxD world to protect it.
I think Naruto himself would be the most interesting. His positive attitude and never - give - up spirit would be really unique in the Highschool DxD world which has a lot of complex power struggles and some rather morally grey areas. He could bring a fresh perspective and also his powerful ninja techniques would make him a force to be reckoned with in battles against devils and angels.
I think Naruto would be the most interesting. His energetic and determined personality would stand out in the Highschool DxD world. He could bring his ninja way of life and values, which are quite different from the devilish and angelic cultures in DxD. His ability to make friends easily might also lead to some really unique interactions with the DxD characters.
Rias from Highschool DxD would be an excellent choice too. Her leadership skills and her role as a devil could be explored in relation to the Naruto characters. She could be intrigued by Naruto's power and try to recruit him into her peerage, or she could learn from Naruto's way of leading his friends and comrades in battle.
Issei could also be a very interesting character to focus on in this fanfic. He is the main character in Highschool DxD. If Naruto and Kuroka enter his world, Issei's reaction to them would be fascinating. He could learn a lot from Naruto's discipline and hard - working nature. And his relationship with Kuroka could also change in new and unexpected ways, adding depth and drama to the fanfic.
Rias Gremory would also be an interesting character to focus on. If she were to interact with Ichigo, her leadership skills and her own goals within the Highschool DxD world could be influenced. Maybe she tries to recruit Ichigo for her peerage, which would lead to all sorts of conflicts and negotiations.
Naruto would be the most interesting. He has such a unique personality and set of skills. His never - give - up attitude would contrast and blend well with the often more self - centered characters in Highschool DxD. He could introduce new values like friendship and loyalty in a more extreme way, and his ninja techniques would be a fresh addition to the battles in the Highschool DxD world.
Naruto and Rias would be an interesting combination. Naruto's positive and determined attitude could contrast with Rias's more calculated and devilish nature. They could learn a lot from each other. Naruto could show Rias about the importance of believing in oneself without relying too much on power, while Rias could introduce Naruto to the complex politics and power structures in her world.