The dynamic within Rias' peerage would be greatly affected. There would be a power vacuum as Naruto is likely a strong member. His departure might cause some members to question Rias' leadership. Maybe they start to worry that if she couldn't keep Naruto, who else might leave? Also, in battles, they would have to find new strategies without Naruto's unique abilities.
In a Naruto - Rias' peerage fanfiction, the story might focus on how Naruto's chakra system interacts with the devil's power. For example, his ability to sense chakra could be enhanced or changed when combined with devilish senses. Also, his relationship with the members of the peerage would be interesting. He could form strong bonds with some, like Kiba in Naruto's world, he might get along well with the werewolf in Rias' peerage.
Naruto in Rias' peerage would be quite a sight. His orange jumpsuit would stand out among the devils. He might use his shadow clones to do multiple tasks within the peerage, like scouting or helping with household chores. His positive attitude would also have an impact on the often - serious devils in the peerage.
In a fanfiction with godlike Naruto in Rias' peerage, Naruto would likely be a dominant force. His godlike status might mean he has even more enhanced versions of his usual powers. He could potentially teach the other members of the peerage some of his ninja ways, like stealth and quick movement. And in battles, he could turn the tide easily with his overwhelming strength.
It could also be due to a power struggle. Naruto is extremely powerful and independent. If Rias or other members of the peerage try to control or limit his power in some way, he would not tolerate it. His power is a part of who he is, and he's used to using it freely to protect others. So this could lead to his departure from the peerage.
In this fanfiction scenario, Naruto's unique abilities like his shadow clones and rasengan would be interesting to see in the context of being kidnapped by Rias Peerage. Maybe the Peerage kidnapped him because they saw his power and wanted to use it for their own purposes. Naruto might resist and start training in secret to get stronger and break free. He could also form an alliance with other characters who oppose Rias Peerage in their world.
Naruto's powers could complement the members of Rias' peerage. For example, his speed could assist in quickly getting into position during battles, which would work well with the more long - range or support - based abilities of some peerage members.
Naruto would probably be angry at first. He's not the type to take being kidnapped lightly. He'd likely try to break free immediately using his strength and ninja techniques.
Perhaps Naruto's departure would lead to Rias trying to win him back. She could send her servants or allies to find Naruto and try to convince him to return. This would create a series of adventures as Naruto tries to avoid being found while also dealing with his own problems.
It's quite possible. Fanfiction writers often come up with interesting and unexpected concepts. Since Naruto and the world of Rias have their own distinct fan bases, combining them in a story where Naruto is a fan of Rias can add a new and exciting twist. You could also check fan - run forums dedicated to either Naruto or High School DxD to see if anyone can point you in the direction of such a fanfiction.