Otaku Girls Unite! was founded after a similar otaku circle, Pretty Garden, was disbanded following the marriage plans of its founder Kaori Makishima. Kaori's younger sister and the last member of Pretty Garden, Saori, felt betrayed by the unexpected leave of her sister and the compliance of the other members. With the support of Saori's friend in the circle, Kanata Kurusu, Saori establishes the online circle.
Unlike Pretty Garden, Otaku Girls Unite is basically a group organized through social networking services. Interested people have to submit a request to the moderator to be approved as a member, and if the request is accepted, that member is automatically added to the list of members. Most of the interactions between members are done online, with members posting under a handle name, although the moderator sometimes organizes real-life meetings for members to chat with each other face-to-face.
Otaku Girls Unite has been established for some time during the start of the light novel series. After Kyousuke Kousaka discovers his sister Kirino's secret hobby as a collector of anime merchandise, Kyousuke advises Kirino to look for a way to share her interests with others. Kirino eventually stumbles upon Otaku Girls Unite, and she sends a request to the group moderator to join the club under the handle name kiririn. Ruri Gokou also sent a similar request as well, using Kuroneko as her handle name. Saori, the moderator, later accepts both requests.
Saori later calls for an IRL meetup in the Cure Maid Café in Akihabara. Kuroneko and Kirino, along with Saori and seven other memebrs attended. Kyousuke is also present but was not part of the meetup but he watched Kirino from a nearby table.
- One of the members present in the IRL meetup has a similar appearance to Manami.