Kayako spent most of her free time with her cat Kuro and was highly anti-social. In the first installment of the "Ju-on" franchise, "", Kobayashi's wife Manami remarks that she remembers Kayako from college and that she found her "creepy". Kayako became highly jealous of Manami and even tried to curse her but failed and eventually gave up. When she attends university, she meets Shunsuke Kobayashi, with whom she falls deeply in love. After the accidental deaths of her parents which didn't seem to faze her, Kayako marries Takeo Saeki, the only person who understands and cares for her, and together, they have a son named Toshio. By now, Kobayashi is Toshio's school teacher, and she falls in love with him again.