First, approach it with an open mind. Don't expect it to be exactly like the original Naruto series. Fanfiction is all about creativity and exploring new ideas.
Well, they might be quite surprised. The Highschool DxD characters are used to their own world of devils, angels and the like. When exposed to Naruto fanfiction, they could be intrigued by the ninja concepts. For example, Issei might be excited about the idea of having ninja powers added to his already powerful abilities. He might think it's really cool how the ninjas in Naruto can use jutsu and he might even start imagining himself using some of those techniques in battle.
Reacting to fanfiction can mean different things. It could be expressing your emotions like surprise, excitement, or disappointment while reading a fan - made story. For example, if a fanfiction takes a beloved character in a completely new and unexpected direction, you might react with shock or intense interest.
When we talk about'reacting to fanfic', it's a broad concept. It can be a very personal experience. Some people might react with enthusiasm, sharing the fanfic widely because they love how the author has reimagined the story. Others might react more critically, perhaps pointing out inaccuracies in the portrayal of the original elements. And then there are those who might have an emotional reaction, like getting really attached to a new character introduced in the fanfic or being moved by a particular scene in the story.
Well, perhaps Naruto finds himself in a world where the Laguz are being oppressed. He decides to fight for them because he sees their struggle as similar to that of his own village. He could use his ninja skills to protect them from any threats, be it other powerful groups or some sort of dark force that wants to take advantage of the Laguz.
It could be a group of power - hungry humans who see the Laguz as a resource to be exploited. They might want to use the Laguz's unique abilities for their own gain, like using their strength in labor or their magical abilities for warfare.
It could be a new group of rogue ninjas who have a vendetta against Konoha. They might be led by a powerful and cunning ninja who has a personal grudge against Naruto or the village in general.
In many fanfictions about Naruto fighting Sasuke during the Chunin Exams, it often showcases their intense rivalry. One common aspect is the display of new jutsus that they might have developed secretly. For example, Naruto could have a new form of the Rasengan, and Sasuke might have evolved his Chidori in some unique way. This makes the fight more exciting as it goes beyond what we saw in the original series.