Well, it depends on what you consider 'good'. There could be fanfictions that blend the elements of Naruto and Highschool DxD in creative ways. For example, some might have Naruto's ninja skills interacting with the supernatural elements of Highschool DxD. However, you may need to sift through a lot of them to find the ones that really stand out in terms of plot, character development, and writing quality.
One possible plot could be that Naruto is summoned to the Highschool DxD world by some sort of magic accident. He then has to navigate the complex social and supernatural hierarchy of the school while also trying to find a way back home. Along the way, he might use his ninja skills to protect his new friends from various threats.
Another theme is mystery. Great Red is not fully understood in the original series, and fanfictions like to play with that. They might create stories where characters are trying to uncover the secrets of Great Red, like its origin or its true intentions. This can add an element of intrigue to the story.
Power and growth are common themes. Since Great Red is such a powerful entity, Issei often experiences significant power - ups in these fanfictions. For example, he might gain new abilities related to Great Red's power.
A popular Highschool DxD Issei and Great Red fanfiction is 'Issei's Great Red Heritage'. It explores the idea that Issei has a long - lost heritage related to Great Red. The story takes Issei on a journey of self - discovery as he tries to understand this new aspect of his identity. It has some really cool twists and turns. Also, 'The Great Red's Influence on Issei' is quite interesting. It shows how Great Red's power and presence start to affect Issei's actions and decisions in the story.
One idea could be that Naruto is somehow transported to the world of Highschool DxD. He could use his ninja skills and chakra in the new world, maybe even teach some of the characters there a thing or two about combat. For example, he could show Issei how to better control his power using chakra control techniques.
The storylines can be combined by creating a common threat. Suppose an enemy emerges that is interested in both the power of the Bijuu and the power sources in Highschool DxD. This would force the characters from both universes to team up. Also, the cultural differences between the Naruto world and the Highschool DxD world can be explored. Naruto could introduce concepts like ninja clans and shinobi training to the DxD characters, while they could introduce him to the complex social hierarchies and supernatural politics in their world.
You can try fanfiction websites like Fanfiction.net or Archive of Our Own. They usually have a wide range of Highschool DxD fanfictions, including those related to Great Red. Just use the search function on the site and type in 'Highschool DxD Great Red' to find relevant stories.
Fanfiction.net is a go - to for many. Just search for 'Highschool DxD Issei Great Red' and you'll get a bunch of results. Some of these fanfictions might be really well - written with interesting plots. AO3 also has a great search function. Try different combinations of the words like 'Issei' and 'Great Red' along with 'Highschool DxD' to narrow down your search. You can also check out some dedicated anime fanfiction forums where fans might share their own works or recommend good ones about Issei and Great Red.
The female characters from Highschool DxD, like Rias, would be intrigued by the unique personalities of the Naruto characters. Rias might see potential in some of them to join her peerage. And the Naruto girls, like Sakura, would be a bit shocked at first by the more revealing outfits and flirty nature of some of the Highschool DxD characters. But over time, they would bond over things like protecting their friends and the school. The Naruto boys would respect the power of the Highschool DxD devils and might even try to incorporate some of their fighting strategies into their own ninja combat styles.