Well, a plot might be that Rias discovers Naruto has a special chakra that could enhance her powers. As a yandere, she decides to keep Naruto close to her at all times. Naruto, not understanding her motives at first, goes along with it. But as time passes, he realizes her true nature. This could lead to a conflict where Naruto has to decide whether to help Rias control her yandere side or find a way to break free from her clutches. It could also involve other characters from both Naruto's and Rias's worlds reacting to their strange relationship.
One way is through a training arc. Naruto could teach Rias some of his chakra control techniques, which in turn could enhance her own power control. Rias could then show Naruto how to use some of her demonic abilities, like summoning minor demons for reconnaissance. Their different abilities could also create unique strategies in a fight. For instance, Naruto could create multiple clones to distract opponents while Rias sneaks up from behind using her stealth abilities. This would not only explore their abilities but also their ability to work together as a team.
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.
In yandere x reader fanfics, yanderes usually display intense emotions. Their love for the reader is not the normal kind; it's more of an obsessive love. They may have a dual personality where they can be extremely sweet and loving one moment, but if they feel threatened in their relationship with the reader, they can turn very dangerous and menacing.
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.
I don't have enough information to specifically say who Rias is in this fanfic. It could be an original character created by the fanfic author, or it could be a character borrowed from an existing series but given a new spin in the fanfic.
Yandere characters in these novels are often extremely possessive. They see the object of their affection as solely belonging to them. For example, they might get angry or even violent if someone else shows interest in their beloved.
One of the well - known yandere characters is Yuno Gasai from 'Future Diary'. She is extremely possessive of her love interest, Yukiteru Amano. Yuno is willing to do anything, including murdering others, to ensure that she is the only one in Yukiteru's life.
A 'yandere fanfic' is a type of fan - created story. 'Yandere' is a Japanese term. In these fanfics, the characters often display extreme, sometimes obsessive and possessive love or devotion, which can lead to rather intense and often dark or unhinged behavior. It's a popular genre in some fan communities, especially those related to anime and manga.