Keiko Sasahara (also known by her work alias "Kyouko") is the younger sister of Kanji Sasahara. Unlike her brother, she is far from an otaku and lives a more socialite, trendy lifestyle influenced by her teenage friends. She starts off openly antagonizing her brother and avoiding his otaku lifestyle, until seeing a pretty boy otaku like Kousaka influenced her to become an unofficial member of Genshiken, despite not being a college student yet.
In Genshiken Nidaime, she works in a hostess club and offers business cards to the male members of Genshiken to get them to come by.
Keiko is a pretty high school senior upon introduction. However, she wore heavy layers of make-up on her face and her appearance is obviously influenced by peer pressure. Her hair is often styled to whatever was popular during the period.
In Genshiken Nidaime, Keiko seems to have matured somewhat, as she wears much less make-up and has a more individual sense of style.
Keiko is superficial, impulsive, stubborn, conniving, and a tease. She comments that she can only date attractive guys, a trait that has gotten her into lots of bad situations. However, her attraction to Kousaka has renewed her interest (somewhat) in her brother's lifestyle. She is a big spender and will often borrow money from Kanji or someone else to go on shopping sprees. Keiko also likes to tease the male members of Genshiken, notably her brother and Madarame.
== Plot ==
Keiko stumbles upon Madarame in the Genshiken room, which startles him (he briefly visualized her as Kasukabe). She then teases Madarame on sticking around campus because he wants to cross paths with Kasukabe again. Madarame vehemently denies this, which angers Keiko. She harasses Madarame up until they were interrupted at the door by Sue. As she leaves, she tells Madarame he's afraid of getting openly rejected and should face heartbreak sometime, even if he is an otaku.