Nene Todoroki is a first year (later second year) student and the head of the Robot Research Club at Ousai. Suzu Hagimura considers her best friend, despite the fact Nene is extremely perverted even compared to the already perverted Shino Amakusa and Aria Shichijō. Unlike the two members of the School Council, Nene demonstrates her perverted nature by her interest in machines, specifically dildos and vibrators and the like. She often wears one, even in school. She also has a tendency to forget to switch them off and is not shy at letting people (most often Suzu or Takatoshi Tsuda) know about it.
Nene is a helpful and kind girl who is happy to make repairs to machines and electronic devices such as clocks and the like. She is also very talented at inventing, having created a life-like robot dog and a Medusa hairpiece with moving snake(dildo) hair. However, she has a huge machine fetish and is constantly tinkering with machines to make more effective sex toys.
Suzu Hagimura (addressed as 'Suzu-chan')
Nene is Suzu's best friend, though the two appear don't have much in common besides good grades. She has been invited to sleep over at Suzu's house on a few occasions, and is also familiar with Suzu's mother. Nene occasionally offers Suzu use of her various sex toys (generally vibrators) and other odd items (such as goggles with strange expressions painted on), but Suzu always refuses. At one point, Nene admitted she made a small vibrator suited for Suzu's size, which Suzu unsurprisingly declined.
However, Nene also built Suzu a customised desk more suited for her height (Suzu had complained that the desks the class used were too tall for her), showing that she really does care about her friend.
Takatoshi Tsuda (addressed as 'Tsuda-kun')
Nene originally had limited contact with Takatoshi barring Student Council business. However, after becoming classmates Nene considers him enough of a friend to offer Valentine's Day chocolates. For his part, Takatoshi acknowledges her intelligence and her ability when it comes to inventing things, but is dismayed by her tendency to wear vibrators in school and leave things like sex toys lying around.
Mutsumi is well-known for being able to get along with everyone, and Nene is no exception. As another of Suzu's closest friends, Mutsumi has joined Nene when sleeping over at Suzu's house. Like with Suzu, Nene occasionally offers Mutsumi use of her assorted sex toys, but the pure Mutsumi simply stares blankly at them.
Shino Amakusa (addressed as 'Amakusa-Kaichou' or simply 'Kaichou/President')
Naruko Yokoshima (addressed as 'Yokoshima-sensei')
- In the first anime series, she made her first appearance in the final episode, which quickly established her interest in machines as well as her high level of perversion (comparable to Shino and Aria).
- She is one of the top students among her grade, ranking fifth in exam scores (Suzu, of course, ranking first).
- During the second season, she hosts her own section titled, "Nene Todoroki's Trivia" that includes information on sexual aids from Japan's ancient history. Suzu and Takatoshi also appear as tsukkomis, and while Nene does include interesting historical facts she often takes it too far and the pair have to calm her down.
- She helps out at the school library, and so may be a member of the Library Club.