The main characters are Naruto and Yasaka. Naruto, with his determination and ability to grow stronger, is a key character. He has his own set of values and a strong will to protect his friends and village. Yasaka, on the other hand, is a respected and powerful leader in the DxD universe. Her intelligence and her ability to command the Youkai Faction make her an important figure. In this fanfic, they would be the ones driving the story forward, through their encounters, exchanges of power, and the development of their relationship.
To write a good Naruto x Highschool DxD fanfic, you need to focus on the character interactions. How would Naruto react to the flirty nature of some Highschool DxD characters? How would the devils view Naruto's strong sense of justice? Also, build a believable world. Since it's a crossover, you have to make it seem like these two very different worlds can co - exist. You can do this by creating a common threat or goal. And don't forget about the pacing. Keep the story moving at a good speed, not too slow or too fast. Throw in some action scenes, but also have some quiet moments for character development.
One possible plot could be that Naruto somehow gets transported to the DxD universe and meets Yasaka. They initially have a misunderstanding as Naruto's chakra and power seem strange to the beings in DxD. But as they get to know each other, they team up to face a common enemy that threatens both the ninja world Naruto comes from and the DxD world. They combine their unique abilities, Naruto's Rasengan with Yasaka's fox - like powers, to defeat the enemy and in the process, they become good friends and learn a great deal about each other's worlds.
Another aspect could be the cultural differences between the two universes. Naruto comes from a more traditional Japanese - inspired world, while Highschool DxD has a more modern, supernatural - focused world. Fanfics might explore how the characters deal with these differences, like Naruto introducing his values of hard work and friendship to the more power - hungry characters in Highschool DxD.
Perhaps Naruto has a unique power that is related to both worlds. He could form a team with some of the DxD characters like Issei. They could go on adventures together, fighting against common enemies. His rasengan might be enhanced by the magic in the DxD world.
Well, one key plot element could be how Naruto and Sasuke adapt to the DxD universe. Maybe they have to deal with the different power systems like Sacred Gears. For example, Naruto's chakra control might interact in an interesting way with the power of a Sacred Gear. Sasuke, with his Sharingan, could have unique ways of seeing through the illusions or strategies in the DxD world.
One popular concept is the power exchange. For example, Naruto's unique jutsu skills being introduced to the Highschool DxD world. Maybe a character from Highschool DxD learning the Rasengan. Another concept could be the character relationships. How would Naruto interact with Issei and his friends? They might form an unlikely alliance against common enemies. Also, the idea of combining the different mythologies in both series is fascinating. The shinobi world's gods and the devils and angels from Highschool DxD could create some really interesting storylines.
Definitely Naruto and Issei. Issei is all about perverted thoughts and power - seeking, while Naruto is more about friendship and protecting his comrades. Their interactions would be full of contrasts and they could learn a lot from each other.
Their powers could combine in a really cool way. Naruto's Rasengan, which is a concentrated form of chakra, could be infused with Sasuke's elemental jutsu, like Fire Style. In the DxD universe, this combined attack could be a powerful weapon against the various enemies. For example, if they face a powerful devil, they could use this super - charged attack to overpower it.
One of the most interesting plot twists could be the sharing of powers. For example, Naruto's ability to use chakra might combine with the unique demonic powers in Highschool DxD in unexpected ways. Maybe a character from Naruto's world gains a devil fruit - like ability from the Highschool DxD universe. Another could be a character from Highschool DxD learning how to use ninjutsu, which would completely change the power dynamics in their own world.