Yusuke could use his spirit detective skills to track down Keiko. He might fight his way through Sakyo and Toguro's minions to reach her.
It's possible that there is a secret power within Keiko that she discovers while kidnapped. She uses this power to break free from her captors. Meanwhile, Yusuke has assembled a team of powerful fighters. They launch a surprise attack on Sakyo and Toguro's hideout. In the chaos, Keiko is able to escape and reunite with Yusuke. Then, together they defeat Sakyo and Toguro once and for all.
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.
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.
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.
Yusuke would likely become more withdrawn.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.
One possible character could be Keiko's father. He is a powerful and influential man in their community. When he finds out about Keiko's kidnapping, he uses all of his resources, including his connections with the local police and his own private security force, to try and rescue her. Then there could be a detective, Inspector Kenji, who is assigned to the case. He has a reputation for being tenacious and smart, and he starts to piece together the clues about Rando's identity and motives.
One possible plot could be that Keiko is caught in the crossfire of a demon battle that Yusuke is involved in. Yusuke, being a spirit detective, has many enemies. Maybe a powerful demon targets Keiko to get back at Yusuke. After her death, Yusuke could go into a deep state of despair and vow revenge. He might journey to the spirit world to find a way to bring her back, facing numerous challenges along the way.
One way the story could develop is that Yusuke goes into a deep state of grief and denial at first. He might start to isolate himself from his friends and the spirit world as well. He could be haunted by memories of Keiko and constantly wonder if there was something he could have done to prevent her death.
If Karasa kidnaps Keiko in a fanfiction, the story could go in many directions. For instance, Keiko might turn out to be much stronger than Karasa expected. She could use her wits and any special abilities she has to try and escape. Or perhaps there are other characters who will come to Keiko's rescue. They could be friends, family, or even strangers who happen to be in the right place at the right time.
Yusuke might cope by throwing himself into his work as a spirit detective. He could try to distract himself from the pain of losing Keiko by taking on more and more dangerous cases. This would be his way of running away from his emotions at first.
In the "Mang Huang Ji," An Yichen likes Huizi. In chapter 1242 of the novel, An Yichen had said to Ning,"I don't wish to become enemies with you. However, the person I like is Keiko. If you were to get together with her, I wouldn't agree to it." In chapter 1243 of the novel, An Yichen had said to Ning,"I like Keiko. I don't want to become your enemy, but if you were to be with her, I would never agree to it." Therefore, An Yichen liked Keiko. While waiting for the anime, you can also click on the link below to read the classic original work of " Full-time Expert "!