2][2][3][a] is a Japanese light novel series written by Tsukasa Fushimi, with illustrations provided by Hiro Kanzaki.

A manga adaptation drawn by Sakura Ikeda was serialized in ASCII Media Works' Dengeki G's Magazine between 2009 and 2011.

Kyosuke Kosaka, a normal 17-year-old high school student living in Chiba,[4] has not gotten along with his younger sister Kirino in years.

One day, however, Kyosuke finds a DVD case of a magical girl anime which had fallen in his house's entranceway.

To Kyosuke's surprise, he finds a hidden eroge inside the case and he soon learns that both the DVD and the game belong to Kirino.

The series then follows Kyosuke's efforts to help his sister to reconcile her personal life with her secret hobbies, while restoring their broken relationship and coming to terms with their true feelings for each other.

Oreimo began as a light novel series written by Tsukasa Fushimi, with illustrations provided by Hiro Kanzaki.

[23] A manga adaptation based on the light novels drawn by Sakura Ikeda was serialized in ASCII Media Works' Dengeki G's Magazine between the March 2009 and May 2011 issues.

Four tankōbon volumes were released under ASCII Media Works' Dengeki Comics imprint between October 27, 2009, and April 27, 2011.

3] began serialization in the July 2011 issue of Dengeki G's Magazine and features Ruri Goko as the main heroine.

A drama CD, based on events from the first and third volumes of the novels as well as a newly written scenario by Tsukasa Fushimi, was released by ASCII Media Works on March 31, 2010.

[39] A 12-episode anime adaptation produced by AIC, directed by Hiroyuki Kanbe, and with screenplay by Hideyuki Kurata aired in Japan between October 3 and December 19, 2010.

In addition to decorating the exterior of the train, the anime characters were featured in in-train advertising to provide passengers with helpful tips about local sightseeing facilities and shops.

[62] The limited edition bundle included an OAD, a sister-talk bonus CD, and an additional game for the PSP.

[71] Anime News Network (ANN) reported in April 2012 that the first nine light novels had collectively sold 3.7 million copies in Japan.

Morrissy stated that the key difference between the two, despite sharing a little sister moe theme, is that Oreimo has committed the ultimate incest taboo due to Kyosuke and Kirino being related by blood, whereas the siblings in Eromanga Sensei lack a blood relation, hence "allowing the romance to play out with a less direct connection to real-life incest".