Sakura's mother has the appearance of a grade schooler, which is why she was mistook as Sakura's younger sister. She likes to cosplay, always dressing up in different attires and having a closet full of different outfits. Despite her appearance, she is shown to have a violent side after consuming alcohol. Rei describes her as "being blind in love for her children" because she has taken pictures of every memorial moment of her daughter (from her first day of school to the first time she ate wasabi). Ironically, she whines that she should have taken more.
One of Ohno's American friends, Susanna (more frequently known as Susie or Sue), is a petite girl with an avid interest in yaoi. Susanna comes off as somewhat harsh and unsociable, and startles the other Genshiken members by using crude anime and manga quotes in Japanese (written in katakana to show her unfamiliarity with the language). As she makes gains in comprehension, her responding solely in quotes makes it unclear just how much Japanese she understands, much to the chagrin of Ogiue and others. Her extensive knowledge of anime and manga quotes suggests that Susanna is well-versed in both, having seen Neon Genesis Evangelion, Kimi ga Nozomu Eien, Fist of the North Star, Saint Seiya, Neko-Yasha, Mahoromatic, Azumanga Daioh, Doraemon and Lupin III, among others. She also seems to be obsessed with Japanese culture. As for her age, it is undetermined, and those who would know (i.e. Ohno) refuse to tell. Susanna wishes to study in Japan in the near future. In the relaunch of the manga, Sue has transferred to Shiiou University and is a first-year student and new club member of Genshiken. She is very close to Ogiue and still spouts various anime and manga quotes. She is employed by Ogiue to be one of her assistants for the official manga Ogiue is writing and drawing. (Source: Wikipedia)
A girl who Shinkur� lived with when he was young and also his sparring partner. Her soft demeanor (albeit with yandere tendencies, triggered by other girls approaching Shinkur�) hides the fact that she is a strong fighter, whom Shinkur� acknowledges to be much stronger than himself, despite her being older by just one year. Yūno is upset that Shinkur� has not realized he was her first love. Even now, she still has feelings for Shinkur�, always finding excuses to spend time with him, such as cooking meals for him. However, her advances tend to be very threatening (most likely because Shinkur� always has another girl with him) and scare him into just letting her hear what she wants. Yūno resents the decision Shinkur� made in deciding to move out her household to live on his own and fears he will change into a hooligan. She has made it very clear that she wants him back in the H�zuki household. Yūno has a younger sister named Chizuru, who is five, who also has a crush on Shinkur�. Even though the H�zuki family are no longer assassins, their grandfather expects Yūno and Chizuru to carry on the H�zuki family martial arts. In the anime, Yūno is much more assertive in her advances towards Shinkur� and does not appear to have the yandere tendencies.
She is yet another tenant of the building Shinkuro lives in. She always wears black and calls herself a very sinful woman. She likes cats and usually keeps to herself except when it comes to Shinkuro and Tamaki. Her attitude can be considered sarcastic most times.
A woman who works as the middleman for the Akuu Company, a secret mercenary group of assassin and skilled individuals.
A 2nd year student at Tenbi Academy and a member of the disciplinary committee. Her maken is called "Maken Scale Compressor" which allows her to alter the volume and mass of inanimate objects.
She is the secretary of the student council as well as a member of the disciplinary committee. She seems to enjoy Yaoi manga. Her maken is called "Comic Star" which allows her to alter the state of physical objects and allows her to use her imagination to project special effects from Manga into reality.