Sayaka was dispatched by Koenma to investigate Yusuke. Interestingly, she played a pivotal role in sparking the relationship between Yusuke and Keiko. She only appears in a single episode.
In the manga, Sayaka is depicted as the spirit of a lonely girl whose parents didn't know how to care for her. Consumed by loneliness, she repeatedly took the soul of Shota, who lacked any sixth sense, slowly causing his health to deteriorate.
Luckily, Yusuke and Botan intervened, helping Sayaka see reason. She promised to leave Shota alone if he would play with her in Heaven when he eventually arrived there. After this, Sayaka spends time with Yusuke and uses this opportunity to test the depth of his and Keiko's love for each other.










