Asuka Shibasaki (Kaho Kōda) was a villainess from "The Case of the Furisode at the Hidden Hot Spring on a Snowy Night", episodes 13.26 and 13.27 of Case Closed (airdates November 22 and 29, 2004). She was a fashion model from Paris who was at the Kotoya Inn (along with several other people) to work on a new TV drama.
Her backstory also revealed that, while attending school at Oodou University, she and her colleague Ema Anzai began selling drugs, though no one would report them out of fear of their influential families. Asuka and Ema often fought with classmate Sakurako Suzuka over their crimes, leading the girls to frame Sakurako, planting drugs in her locker to incriminate her. With the accusations being believed by many, the despondent Sakurako was driven to commit suicide by jumping from the university roof, allowing the evil Asuka and Ema to avoid being punished for their crimes.
In the episode's present events, Asuka and Ema reunited at the Kotoya Inn for the TV drama, where they were introduced teasing singer Harumi Fukatsu (Sakurako's friend who had also been invited to join the TV show) by claiming that her fame wouldn't last long. Another member of the team for the TV drama was novelist Eri Akechi, who unbeknownst to Asuka and Ema, was Sakurako's sister who had joined the drama cast as a means of taking revenge on the women she blamed for her sister's suicide. Eri went about killing Asuka while she was bathing in the inn's hot spring room, knocking her out with a stun gun before stabbing her to death with a holy knife and leaving her body in the hot spring. Eri also placed obis (kimono sashes) into the spring as well to mirror the local legend of the "Furisode Hannya", which bore similarities to what happened between Asuka, Ema, and Sakurako.