Kyoko is the head and only member of the Eiken club's science division as well as a former science club member. Despite resembling a small child she is older than she seems. Even though from a photograph taken from when she was younger she doesn't appear to have grown in height much.
Although she acts tough she likes cute things, such as kittens and a fictional action hero in the series called Nekomanman.
She is secretly quite jealous of the other girls in the club for having such bodies while she still resembles a small child, but hides it by saying since she plans to be a scientist she doesn't need to be tall or curvaceous. In the previously mentioned photograph her mother is about as tall as an ordinary person so it might be possible that her father was quite short, or she has yet to go through a growth spurt. In a dream Densuke had Kyoko was seen to be tall and beautiful 10 years into the future.
Her father passed away several years before the series leaving her mother to raise Kyoko alone. However she was recruited as the top engineer for a foreign company, leaving Kyoko by herself. Even though Kyoko says she is proud of her mother she still misses her terribly.
Kyoko appears to live in a science facility built in a large canyon. The exact location is unknown.
She usually treats Densuke like a guinea pig for her inventions, but it is also possible she likes him as well, evidenced when she repeatedly threatens him when he, like with all the other girls, ends up doing something she considers perverted. Although due to her appearance it is much more downplayed than with the other girls.
In the OAV she is voiced by Mai Kadowaki in Japanese and Rebecca Forstadt in english