|Junko Asami (OVA)||Belinda Bizic-Keller (OVA)|
|Mamiko Noto (TVA)||Karen Neill (TVA)|
Sayoko was once Keiiji's love interest, but she turned him down after he asked her if she could go to the museum with, telling Keiiji that going to the museum is for boring old people, and saying she might reconsider going on a date with him if he grows a few inches taller.
However, Sayoko becomes jealous after she sees Keichi with Belldandy, after Keichi made a wish for Belldandy to stay by his side forever, making Sayoko jelous after several men, who fell for her, dumped her over Belldandy and tried to make her find a way to seperate Keiiji and Belldandy.
When class was starting, Sayoko wanted Belldandy, who was sitting next to Keiiji, to move out of her seat, but Belldandy came up with a way for Sayoko to sit between her and Keiiji. When the teacher of the classroom noticed Belldandy and said he never seen her before, this gave Sayoko the idea to go to the college professor to make him do a background check on Belldandy, to see if she is an exchange student. Toriachi and Otaki heard about this, so they went to Keiiji and Belldandy to make them hack into the school's system, to put down false information about Belldandy.
Sayoko, still not giving up, goes over to Keiiji and Belldandy and tells Belldandy that the college professor wants to see her. With her gone, she asks Keiiji about his feelings about her, but then water dumped over her as it was part of the system force that comples Keiiji from leaving Belldandy.
Belldandy eventually senses Sayoko's desire to separate her from Keiichi and warns him that she (Sayoko) is in grave danger. She explains that the System Force becomes more active depending on the strength of the force trying to break them apart and the stronger Sayoko's desire is, the stronger System Force reacts; thus if Sayoko continues her reckless schemes, she could be in grave danger. As they discuss the ramifications of Sayoko's actions, Sayoko is seen talking to another girl about the situation. Sayoko pridefully boasts that she can easily turn a man like Keiichi into her lovesick slave in less than three days, betting her BMW as collateral with her friend. As the two women agree to the terms of the wager, Belldandy feels the System Force growing stronger. In the following week, Sayoko renews her efforts to win Keiichi over, her requests including rides in her BMW, invitations to dinner, and even attempts to invite him over to her house. Each attempt fails miserably thanks to the System Force causing her misfortunes, such as breaking her car engine, inciting a dog attack, and blasting her away with an unusually powerful wind gust. Although Belldandy manages to shield her from harm using divine powers, the couple begins to worry for Sayoko's safety.
Despite constant interference from the System Force, Sayoko perseveres and manages to hand her invitation to Keiichi, but the divine power responds by creating a blizzard over Nekomi Institute. While she understands the danger posed by the snowstorm, Sayoko remains bitter that he didn't even have the courtesy to call her, only to receive a visitor at the door. While surprised he was able to make it, she is about to declare victory over Belldandy, only to find out that Keiichi brought her along. He hands her a cake made by Belldandy to apologize for everything that happened, but Sayoko is touched that they came all the way to her house for something so minor.
She inwardly acknowledges that Keiichi and Belldandy's bond might be beyond her ability to break. Sayoko then invites them to stay a while and eat with her, admitting defeat... For now. As the tension lifts, Belldandy notices the snow has stopped. The next day at school, Sayoko gives her car to her friend without complaint, humorously replying that the engine is broken.
Time passed, the new semester has begun. Sayoko and Art Club where she belongs to attempt to attract new members, only to be overshadowed by the Auto Club. The next day she notices that the Freshman playboy Toshiyuki Aoshima who tries to win Belldandy over from Keiichi, but she decides to help out for a change. Sayoko reveals to Keiichi that Aoshima is her cousin, and explains his method of getting girls to sleep with him, much to Keiichi's shock. As he rides off to save Belldandy, Sayoko describes herself as being too proud to win his heart on the rebound, this being the reason why she decided to lend them a hand this time.
After being blasted through the ceiling of a hotel while trying to pursue Belldandy thanks to Belldandy's goddess sister Urd, Aoshima finds himself questioning what type of power she (Belldandy) has, only to be interrupted by Sayoko. She claims to have the same suspicions, so the two cousins team up to discover the truth. They spend the day stalking Belldandy and Keiichi with a video camera in hand, but their plot is foiled by Urd, who continually follows them around delivering all sorts of punishment on them. The troublesome duo finds it bizarre that she was seemingly able to find them anywhere they went, but Sayoko shrugs it off, saying they should hurry and get the tape analyzed by the parapsychology club on campus. Aoshima attempts to produce the footage only to learn that the tape is missing, angering his cousin. They follow Keiichi and the others back to the temple, but Aoshima ends up losing himself while spying on Belldandy in the shower. Sayoko takes over for him only to get them caught, which results in Urd washing them away with a powerful water spell. The next day they kidnap Keiichi with help from the S&M Club, but by the time Belldandy comes to the rescue, Urd has already saved the day. Keiichi then tells her to catch Sayoko and Aoshima before they have their video tape analyzed, so Belldandy flies after them by enchanting a broomstick. She admits to being a Goddess when asked by Sayoko (claiming goddesses do not lie), but they refuse to believe it and have the tape analyzed anyway. Urd then reveals she edited the footage to make their magic look like cheap special effects, puzzling Aoshima and Sayoko even more. Belldandy tries to get Aoshima and Sayoko to believe she's a goddess, this time by revealing her true form.
Personality and Trait
Sayoko greatly enjoys flaunting her gorgeous appearance and money while basking in the warmth of admiration she receives from her many admirers. She appears to thrive on these aspects to the point of intense jealousy whenever a potential rival appears, as was the case when Belldandy first appeared on the NIT campus, stealing much the attention and praise that was once her own. During times such as these, Sayoko will often dwell on her frivolous losses and seethe in anger, even plotting ways to take vengeance on the people she believes are responsible for her so-called misfortune. Her yearning of being Queen of the NIT Campus is so great, that she has even joined hands with the Demon Marller (whose power equals to Belldandy) in order to regain the popularity she believes is rightfully hers, even scheming to get rid of Belldandy or humiliate her.
Her obsession with defeating Belldandy appears to stem primarily from her own pride, since she has competed with the Goddess multiple times while trying to outdo her (which is a tall order since Belldandy is a goddess, while Sayoko is just a human). Despite her several losses to Belldandy, it eventually gets to the point where she starts to enjoy their little contests. Sayoko has even tried to win Keiichi away from Belldandy, but her attempts to do so have little success due to his devotion to the Goddess and the divine system called System Force to ensure any and all attempts to separate Keiichi and Belldandy thwarted. Even with Marller's help, this task has proven near impossible to achieve.
Having come from a wealthy family and having a have-it-all upbringing, Sayoko has been spoiled to the point where she sees herself as entitled to get whatever she desires. Despite her self-centered and materialistic views, Sayoko occasionally displays loneliness and a deeper sense of awareness, at times feeling useless and empty/superficial regardless of all the attention she receives. As the series progresses, she begins to display a thirst for the companionship of someone who isn't only attracted to her merely because of her money and looks. She seemingly develops feelings for Keiichi whom she once callously jilted, noting to herself that having him around gives her a strange sensation, and makes her feel less lonely.