One possible fanfiction idea could be that Rias' sick brother is a key factor in a power struggle within their supernatural world. Naruto, being an outsider with his own set of skills and values, could get involved. Maybe he forms an alliance with Rias to protect her brother from those who would use his illness to their advantage.
The plot could involve Naruto using his knowledge of chakra to diagnose Rias' brother's illness. He might discover that it's not a normal sickness but something related to the supernatural nature of their world. For example, his chakra flow could be disrupted by a dark magic spell.
In some 'Naruto Rias sick' fanfiction, it could be that Rias is cursed by an enemy. Naruto, being the hero he is, feels responsible for helping her. He uses his knowledge of chakra and seals to try and break the curse. Meanwhile, Rias is weak from the curse and her devil powers are waning. As Naruto delves deeper into finding a solution, he uncovers secrets about both worlds that are related to the curse. This could lead to a series of adventures where they have to overcome various obstacles together, all while Rias is struggling with the effects of the sickness.
I'm not sure specifically which 'Naruto Rias sick' fanfictions are out there. However, you can start by looking on popular fanfiction websites like FanFiction.net or Archive of Our Own. Search for the tags 'Naruto' and 'Rias' and then skim through the results to find ones that might involve a sick or ill situation for the characters.
They would likely start with some mutual curiosity. Naruto would be intrigued by Rias's devilish appearance and powers, while Rias would be interested in Naruto's ninja abilities. They might exchange stories about their respective worlds, with Naruto talking about his village and his friends, and Rias sharing about the devil society. Interaction could also involve sparring sessions to test each other's strength.
Definitely. The concept of combining different fictional universes in fanfiction is quite common. In a 'Naruto is Rias' Familiar' fanfiction, we could expect to see Naruto's ninja skills and powers being incorporated into the world of High School DxD. Maybe Naruto would use his shadow clone jutsu in battles in the DxD universe or his rasengan against some of the devils. It could also explore how Naruto, with his strong sense of justice and loyalty, would interact with Rias and the other characters in her peerage.
In this fanfiction, Naruto might show his jealousy in his typical brash way. He could be all fired up and ready to challenge the person who is making him jealous. Rias, on the other hand, would be more calculating in her jealousy. She might use her devilish powers and influence to subtly drive a wedge between the person causing the jealousy and the object of her affection. They could end up teaming up to get rid of the 'competition' in a rather comical or intense way depending on the tone of the fanfiction.
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.
One possible reason could be that the storylines in the fanfiction are focused on different aspects or relationships within the fanfic's universe. Maybe the author wants to explore other characters' interactions more deeply and Naruto just doesn't fit into those particular plotlines they have in mind.
If Naruto kills Rias in a fanfiction, it might be due to a misunderstanding. Naruto is known for his strong sense of justice. Perhaps in this fanfic, Rias is misrepresented as a threat to Naruto's world or his friends. But it's still quite a shock as they are from different fictional universes with their own moral compasses.