In this fanfiction, Shion and Kiyoki are likely two characters created by the fanfic author. They could be based on certain archetypes like Shion might be the more adventurous type, always looking for new experiences. Kiyoki, on the other hand, could be more reserved and calm. But when they meet, their personalities start to complement each other.
In the fanfiction, their relationship could develop gradually. Naruto, being the friendly and outgoing person he is, would approach Shion with an open heart. Shion, initially guarded, would be intrigued by Naruto. As they spend time together, Naruto would introduce Shion to his friends in Konoha. She would be welcomed into his world. Shion would in turn show Naruto the beauty and mystery of her own world. They would support each other through difficult times, like when Naruto faces political opposition in the village for being with Shion. Their love would grow stronger through these trials, and they would ultimately get married.
At first, it might be a bit rocky. Naruto is used to the fast - paced life in Konoha, while Shion has her own ways from her village. But as they share experiences, like cooking together or training each other, they start to appreciate each other more. Naruto would show Shion the fun side of life in Konoha, and Shion would introduce Naruto to the spiritual side of her village's shinobi culture. Over time, their love and respect for each other would grow stronger.
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.
I don't have enough information to say who exactly 'Strongest Hero Shion' is. Since I'm not familiar with the specific novel, it could be a character created by the author with unique powers and a backstory.
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.