In fanfiction, Kurama is often depicted as calm, intelligent and elegant. His plant - based powers are usually a central part of the stories, whether he's using them for combat or for more peaceful purposes like healing. Yusuke, on the other hand, is usually portrayed as hot - headed but with a good heart. His impulsive nature gets him into trouble but also makes him a very dynamic character. He's also known for his strong fighting spirit.
Another aspect could be a fanfiction set in an alternate universe where Genkai and Younger Toguro are allies against a greater evil. They could use their combined skills and knowledge to fight off powerful demons. This would show a different side of their relationship, more of a partnership than what we might expect from their normal interactions in the original series.
In such a fanfiction, perhaps Toguro kidnaps Keiko to use her as bait to lure Yusuke. He might think that Yusuke will come to rescue her no matter what, and then he can have a rematch with Yusuke on his own terms.
One idea could be a crossover with a popular shonen series like Naruto. Toguro could be brought into the Naruto world as a powerful rogue ninja. His immense strength and dark nature would make him a formidable adversary for the Konoha ninjas. Another idea is a crossover with One Piece, where Toguro joins a pirate crew as a fearsome fighter, perhaps with his own hidden motives for being on the Grand Line.
In some fanfiction, they could be involved in a tournament together. Genkai as a mentor figure guiding Younger Toguro through the challenges of the tournament, teaching him strategies and how to control his emotions during the battles. This would show their relationship evolving in a high - stress environment.
Yusuke would likely become more withdrawn.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.
His friends like Kuwabara and Kurama might also join in the rescue. Kuwabara with his tough fighting spirit and Kurama with his cunning and powerful abilities could be a great help in getting Keiko back from Toguro.
Well, perhaps in this fanfiction, Sakyo and Toguro kidnap Keiko because they think she has some special power or knowledge. Maybe they believe she can lead them to a powerful artifact. Keiko, being a strong - willed character, tries to resist them and find a way to escape. Meanwhile, her friends are desperately searching for her, and they end up having to team up with some unexpected allies to take on Sakyo and Toguro.
In a crossover with the Fate series, Saber could be paired with Toguro. Saber's sense of honor and her noble fighting style would clash with Toguro's brute force and underhanded tactics. It would create a really interesting dynamic, whether they are on opposing sides or forced to work together for some greater purpose.