In a fanfic, Risa could be a talented artist who is asked to create a portrait of Sirzech for an important school event. As she spends time observing him and getting to know him better, they start to have feelings for each other. But there could be a conflict when some jealous students try to sabotage the portrait and their relationship, creating drama and tension.
Perhaps a fanfic where Risa is a new transfer student and Sirzech is assigned to show her around. Along the way, they get involved in a mystery involving missing students. Their relationship could grow as they work to solve this mystery, with Sirzech protecting Risa at times and Risa using her wits to help Sirzech in making crucial decisions.
Maybe there's a prophecy in the Highschool DxD universe that involves Issei and Mirana. They are brought together by fate, but they don't know it at first. Issei is on his usual adventures, fighting devils and whatnot, and Mirana gets caught up in his world. Their relationship starts to form as they work together to figure out the prophecy and in the process, they fall in love. There could be a lot of action, drama, and some romantic moments along the way.
The plot could involve a power - transfer situation. Sirzechs, being a very powerful devil, might decide to transfer some of his power to Rias for a special mission. This would put Rias in a new position of strength but also bring new responsibilities. She would have to learn to control this new power while also dealing with the jealousy or suspicion of other devils.
The plot could also involve Naruto being mistaken for a new type of devil or a strange being in the Highschool DxD world. His chakra could be seen as a very unique power source. He might have to go to the high school in the DxD world and get into all kinds of adventures, like dealing with the pervy situations that Issei often finds himself in, but with his own Naruto - style humor and strength.
Well, in a 'Naruto x Greyfia Highschool DxD' fanfiction, perhaps Naruto is a new transfer student in the Highschool DxD. Greyfia could be a popular student there. Naruto's positive and energetic attitude might attract Greyfia's attention. They could start off as friends and gradually develop a deeper relationship. Maybe they get involved in the supernatural battles of the DxD world together, with Naruto using his Rasengan and other jutsu while Greyfia uses her demonic powers. And as they spend more time together, they learn from each other's worlds and values.
One possible plot could be that Naruto is somehow transported to the Highschool DxD universe and meets Gabriel. They might team up to face a common threat that is endangering both the ninja world and the supernatural world of Highschool DxD. Naruto's unique skills as a ninja could be combined with Gabriel's angelic powers in an epic battle against evil forces.
Well, one possible plot could be that Natsu is betrayed in his own world and somehow ends up in the DxD Highschool universe. Maybe he has to deal with the different power dynamics and politics there while also trying to figure out who betrayed him in his original world. He might form new alliances with the characters in DxD Highschool and use his unique abilities to survive and seek revenge for his betrayal.
One possible plot could be that Naruto, with his godlike powers, ends up in the world of Highschool DxD. He might join the Occult Research Club and use his unique abilities to protect the club from various threats. His ninja skills and super - powered jutsus could be a huge asset in battles against devils, fallen angels, and other supernatural foes.
One possible plot could be Naruto being somehow transported to the world of Highschool DxD. He could use his ninja skills and chakra in the battles against the devils and fallen angels in that world. Maybe he teams up with Issei and his group, and Naruto's unique jutsus like Rasengan and Shadow Clone Jutsu surprise everyone.
In a 'Naruto x Kuroka Highschool DxD' fanfiction, the plot could be that Naruto is on a mission to find a powerful artifact that has been lost in the DxD world. Kuroka, being a local with knowledge of the hidden places, offers to help him. Along the way, they discover that there is a conspiracy to use the artifact to take over the school. They must race against time to stop the villains. Naruto's determination and Kuroka's slyness work well together as they outwit the bad guys.