Yusuke would likely become more withdrawn. He was always a bit of a rough - around - the - edges character, but Keiko's death would make him more somber. He might lose his sense of humor that he sometimes showed around her.
Well, Kurama might train Naruto by teaching him how to better control and access chakra. Since Kurama has a vast amount of chakra, it could show Naruto unique ways to harness and use it. For example, it could guide Naruto in creating more powerful and complex jutsu by using their combined chakra in a more efficient way.
I'm not sure specifically who 'Yusuke Kishi' is in 'The New World' novel as there could be many characters with different roles. Maybe he is a minor character that is not widely known among general readers.
One interesting hiei x reader story could be about a journey together. Maybe the reader is a powerful being as well, and they meet Hiei in a dangerous forest. They start off as rivals, constantly challenging each other's skills. But as time passes, they realize they have more in common than they thought and slowly develop feelings for each other.
One common theme is the culture shock. Since they come from different anime universes, their ways of life, values, and even magic systems can be very different. Another theme could be the forming of an unlikely friendship or alliance. Given their different personalities, it's interesting to see how they come to trust and rely on each other.
There are definitely some 'kagome meets hiei fanfiction' pieces. When you read these crossovers, you might notice how the authors play with the distinct personalities of Kagome from Inuyasha and Hiei from Yu - Yu Hakusho. They might create scenarios where Kagome's kind - heartedness clashes or meshes with Hiei's more brooding nature. This can lead to some really interesting and unique storylines that are worth exploring.
In fanfiction, the fact that they come from different parts of the Yu Yu Hakusho world adds to the allure. Botan is a guide to the afterlife and Hiei is a demon. Their different backgrounds and the potential for them to bridge the gap between their worlds can create complex and exciting plots. For example, a story could explore how they deal with the cultural differences between the spirit world and the demon world while falling in love. There could be conflicts arising from their respective duties and loyalties, which can be delved into in great detail in fanfiction.
It could develop as Naruto spends more time in the mental space where Kurama resides. They start to communicate better, understand each other's motives, and gradually form a deeper connection. This might involve Naruto learning about Kurama's pain and loneliness over the years, which makes Kurama more open to Naruto. As a result, their bond becomes stronger and more symbiotic, allowing them to share power more effectively and support each other in different situations.