Ore no Imōto ga Konna ni Kawaii Wake ga Nai

Ore no Imōto ga Konna ni Kawaii Wake ga Nai (俺の妹がこんなに可愛いわけがない), also known as Oreimo for short, is a Japanese light novel series written by Tsukasa Fushimi, with illustrations provided by Hiro Kanzaki. The first volume was published by ASCII Media Works under their Dengeki Bunko imprint in August 2008; as of November 2010, seven volumes have been released. A manga adaptation drawn by Sakura Ikeda started serialization in the March 2009 issue of ASCII Media Works' Dengeki G's Magazine. A 12-episode anime adaptation produced by AIC aired in Japan between October and December 2010. Four additional original video animation episodes will be released in June and July 2011.

Plot
Kyōsuke Kōsaka, a normal 17-year-old high school student living in Chiba, has not gotten along with his younger sister Kirino in years. For longer than he can remember, Kirino has ignored his comings and goings and looked at him with spurning eyes. It seemed as if the relationship between Kyōsuke and his sister, now fourteen, would continue this way forever. One day however, Kyōsuke finds a DVD case of a magical girl anime which had fallen in his house's entrance way. To Kyōsuke's surprise, he finds a hidden adult game inside the case and he soon learns that both the DVD and the game belong to Kirino. That night, Kirino brings Kyōsuke to her room and reveals herself to be an otaku with an extensive collection of moe anime and younger sister-themed adult games she has been collecting in secret. Kyōsuke quickly becomes Kirino's confidant for her secret hobby.

Characters

 * Kyōsuke Kōsaka (高坂 京介)
 * Kyōsuke is the 17-year-old main character of Oreimo. He has a distant relationship with his sister, feeling that this will never change. However, this suddenly changes when he finds one of her adult games and learns that she is an otaku. Through this, he tries to be a supportive older brother while realizing he himself knew very little about his sister, such as being almost flawless at school to working as a model. Later on, he takes up more of his role as an older brother to her, and appears to be able to tell what she is thinking or really meaning to say despite her tsundere personality. Despite this, she is generally the dominant person in their relationship, with Kyōsuke being shown to be openly intimidated by her, only standing up to her in truly serious situations. Kyōsuke prefers to have a relatively peaceful and simple life despite the fact that the drama Kirino brings makes his life anything but peaceful.
 * Kyōsuke is the 17-year-old main character of Oreimo. He has a distant relationship with his sister, feeling that this will never change. However, this suddenly changes when he finds one of her adult games and learns that she is an otaku. Through this, he tries to be a supportive older brother while realizing he himself knew very little about his sister, such as being almost flawless at school to working as a model. Later on, he takes up more of his role as an older brother to her, and appears to be able to tell what she is thinking or really meaning to say despite her tsundere personality. Despite this, she is generally the dominant person in their relationship, with Kyōsuke being shown to be openly intimidated by her, only standing up to her in truly serious situations. Kyōsuke prefers to have a relatively peaceful and simple life despite the fact that the drama Kirino brings makes his life anything but peaceful.


 * Kirino Kōsaka (高坂 桐乃)
 * Kirino is Kyōsuke's 14-year-old younger sister. She is mature for her age with a cold, tsundere-like personality. She has a strong "little sister" fetish and owns many adult games with older brother and little sister themes; she got a job modeling to pay for her hobby. Despite her interests, she states she does not know why she started liking it, though it is suggested that she has a brother complex and is using the games as a surrogate to this. She often denies such feelings and believes the 2D and 3D worlds should be kept separate. Nevertheless, she is shown to be very frustrated when her brother is with or shows interest in other girls, such as Manami, who she accuses as being "all over" Kyōsuke. Likewise, she frequently forces Kyōsuke to spend time with her, whether it is playing games or taking her out, but denies that she actually enjoys the time they spend together. She goes as far as hitting him after he complains that she is ordering him around as if he was her boyfriend, and goes out of her way to sabotage his time with another girl. Despite stating she only likes her adult games because of their cuteness, she shows a perverted side to herself when playing. She uses the screen name Kiririn when with her otaku friends.
 * Kirino is Kyōsuke's 14-year-old younger sister. She is mature for her age with a cold, tsundere-like personality. She has a strong "little sister" fetish and owns many adult games with older brother and little sister themes; she got a job modeling to pay for her hobby. Despite her interests, she states she does not know why she started liking it, though it is suggested that she has a brother complex and is using the games as a surrogate to this. She often denies such feelings and believes the 2D and 3D worlds should be kept separate. Nevertheless, she is shown to be very frustrated when her brother is with or shows interest in other girls, such as Manami, who she accuses as being "all over" Kyōsuke. Likewise, she frequently forces Kyōsuke to spend time with her, whether it is playing games or taking her out, but denies that she actually enjoys the time they spend together. She goes as far as hitting him after he complains that she is ordering him around as if he was her boyfriend, and goes out of her way to sabotage his time with another girl. Despite stating she only likes her adult games because of their cuteness, she shows a perverted side to herself when playing. She uses the screen name Kiririn when with her otaku friends.


 * Manami Tamura (田村 麻奈実)
 * Manami is Kyōsuke's childhood friend. She wears glasses and is described as 'plain'. She has a crush on Kyōsuke and blushes to his compliments. Due to the time they spend together, the people around them assume they are dating. According to Kyōsuke, her speech patterns resemble that of a grandmother.
 * Manami is Kyōsuke's childhood friend. She wears glasses and is described as 'plain'. She has a crush on Kyōsuke and blushes to his compliments. Due to the time they spend together, the people around them assume they are dating. According to Kyōsuke, her speech patterns resemble that of a grandmother.


 * Saori Makishima (槇島 沙織) Saori Vageena (沙織・バジーナ)
 * Saori is the leader of the "Anime Girls Unite!" group on the Internet, whom Kirino meets in a meet-up. She wears very thick glasses (shown as swirls) and speaks with an exaggerated tone. She is a fan of Gundam and is also a collector of their model kits. Saori is an aristocrat from a wealthy family, and speaks with a highly formal voice outside of meeting with her friends. She is tall and usually has to get cosplay tailor made. As Kyōsuke says, Saori is drastically different from how she communicates through the Internet and through phone or speaking with her in person, to which she seemingly switches to a refined and sophisticated persona. According to Kyōsuke in the light novels, she is dressed as a typical otaku from television but has the body of a supermodel. Despite her cheery attitude, Saori is quite lonely, living by herself, and has always feared that one day her true friends (Kirino, Kyōsuke, and Ruri) would leave her in a similar way that her older sister (who got married and moved away) left her.
 * Saori is the leader of the "Anime Girls Unite!" group on the Internet, whom Kirino meets in a meet-up. She wears very thick glasses (shown as swirls) and speaks with an exaggerated tone. She is a fan of Gundam and is also a collector of their model kits. Saori is an aristocrat from a wealthy family, and speaks with a highly formal voice outside of meeting with her friends. She is tall and usually has to get cosplay tailor made. As Kyōsuke says, Saori is drastically different from how she communicates through the Internet and through phone or speaking with her in person, to which she seemingly switches to a refined and sophisticated persona. According to Kyōsuke in the light novels, she is dressed as a typical otaku from television but has the body of a supermodel. Despite her cheery attitude, Saori is quite lonely, living by herself, and has always feared that one day her true friends (Kirino, Kyōsuke, and Ruri) would leave her in a similar way that her older sister (who got married and moved away) left her.


 * Ruri Gokō (五更 瑠璃) Kuroneko (黒猫)
 * Ruri is another otaku girl who lives near Kirino and often wears gothic lolita clothing based on a character from her favorite anime, even during hot weather, and will sometimes add cat ears and a tail. Due to both of their tsundere-type personalities, she constantly clashes with Kirino when it comes to anything. However, Kuroneko does care for Kirino. Unlike Kirino who likes little sister-themed games, Kuroneko enjoys teen-centered fantasy anime. She often mentions "dark magic", claiming that she has it, usually to Kirino or to Kyōsuke. She is noted to have a very high vocabulary, to where Kirino commented she needed to use a dictionary to translate her novel. Kuroneko actually wears red contact lenses to make her bluish eyes seem red. Kuroneko also has younger sisters, whom she dearly cares for. At school, Kuroneko wears normal clothes and at home, takes care of her younger sisters. In the anime, she later refers to Kyōsuke as "nii-sama" due to her wishing to have an older brother and suggesting to annoy Kirino.
 * Ruri is another otaku girl who lives near Kirino and often wears gothic lolita clothing based on a character from her favorite anime, even during hot weather, and will sometimes add cat ears and a tail. Due to both of their tsundere-type personalities, she constantly clashes with Kirino when it comes to anything. However, Kuroneko does care for Kirino. Unlike Kirino who likes little sister-themed games, Kuroneko enjoys teen-centered fantasy anime. She often mentions "dark magic", claiming that she has it, usually to Kirino or to Kyōsuke. She is noted to have a very high vocabulary, to where Kirino commented she needed to use a dictionary to translate her novel. Kuroneko actually wears red contact lenses to make her bluish eyes seem red. Kuroneko also has younger sisters, whom she dearly cares for. At school, Kuroneko wears normal clothes and at home, takes care of her younger sisters. In the anime, she later refers to Kyōsuke as "nii-sama" due to her wishing to have an older brother and suggesting to annoy Kirino.


 * Ayase Aragaki (新垣 あやせ)
 * Ayase is Kirino's friend and classmate who works as a model alongside her and is also her best friend. Ayase is a friendly, nice, and refined lady, but becomes agitated and somewhat violent at the thought that she is being lied to, which she hates above all else. She tends to believe what she sees on the news. Therefore, she disapproves of anime and manga, calling it a disgusting hobby, especially adult games, due to the media portrayal that otaku will eventually become criminals.
 * Ayase is Kirino's friend and classmate who works as a model alongside her and is also her best friend. Ayase is a friendly, nice, and refined lady, but becomes agitated and somewhat violent at the thought that she is being lied to, which she hates above all else. She tends to believe what she sees on the news. Therefore, she disapproves of anime and manga, calling it a disgusting hobby, especially adult games, due to the media portrayal that otaku will eventually become criminals.


 * Kanako Kurusu (来栖 加奈子)
 * Kanako is Kirino and Ayase's fellow friend, classmate and model, who has sometimes swaps between a cute personality to a bratty one. She enters a lot of idol auditions and is a talented singer, able to memorize a song after hearing it only once. She is unaware of Kirino's hobby and generally finds anime childish and otaku disgusting, though she is on one occasion tricked into cosplaying as Kirino's favorite anime character, Meruru, for a contest.
 * Kanako is Kirino and Ayase's fellow friend, classmate and model, who has sometimes swaps between a cute personality to a bratty one. She enters a lot of idol auditions and is a talented singer, able to memorize a song after hearing it only once. She is unaware of Kirino's hobby and generally finds anime childish and otaku disgusting, though she is on one occasion tricked into cosplaying as Kirino's favorite anime character, Meruru, for a contest.


 * Daisuke Kōsaka (高坂 大介)
 * He is Kirino and Kyōsuke's domineering father. He is a high ranking officer in the police and has a no nonsense policy at home. He does not like the fact that Kirino is a model, but allows her to do so if she does well in school. He is severely against otaku, believing them to be a waste of a life, so when he finds out Kirino is one, he initially orders her to throw away everything otaku-related in her room. After being given a verbal beat-down by his son, he allows her to keep everything except for the hentai, and even that he reluctantly allows Kyōsuke to keep after the latter claims ownership of it. It is shown he truly does care for Kirino despite his gruff exterior, as he owns every article and picture of all her accomplishments.
 * He is Kirino and Kyōsuke's domineering father. He is a high ranking officer in the police and has a no nonsense policy at home. He does not like the fact that Kirino is a model, but allows her to do so if she does well in school. He is severely against otaku, believing them to be a waste of a life, so when he finds out Kirino is one, he initially orders her to throw away everything otaku-related in her room. After being given a verbal beat-down by his son, he allows her to keep everything except for the hentai, and even that he reluctantly allows Kyōsuke to keep after the latter claims ownership of it. It is shown he truly does care for Kirino despite his gruff exterior, as he owns every article and picture of all her accomplishments.

Light novels
Ore no Imōto ga Konna ni Kawaii Wake ga Nai began as a light novel series written by Tsukasa Fushimi, with illustrations provided by Hiro Kanzaki. The first volume was published by ASCII Media Works under their Dengeki Bunko imprint on August 10, 2008; as of November 10, 2010, seven volumes have been released.

Manga
A manga adaptation based on the light novels drawn by Sakura Ikeda began serialization in the March 2009 issue of ASCII Media Works' magazine Dengeki G's Magazine sold on January 30, 2009. The first tankōbon volume was released on ASCII Media Works' Dengeki Comics imprint on October 27, 2009; the third volume followed on December 10, 2010.

Drama CD
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. The CD stars Ayana Taketatsu as Kirino and Yūichi Nakamura as Kyōsuke.

Internet radio show
An Internet radio show entitled Ore no Imōto ga (Radio de mo) Konna ni Kawaii Wake ga Nai (俺の妹が(ラジオでも)こんなに可愛いわけがない) to promote the anime adaptation began streaming on August 13, 2010 via the official website of the anime. The show is hosted by Ayana Taketatsu, who plays Kirino in the anime, and Kana Hanazawa, who plays Kuroneko. As of November 2010, seven shows have been broadcast, with new episodes being streamed every second and fourth Friday of the month.

Anime
A 12-episode anime adaptation produced by AIC and directed by Hiroyuki Kanbe aired in Japan between October 3 and December 19, 2010. The series will be released over eight BD/DVD compilation volumes, with two episodes each, between December 22, 2010 and July 27, 2011. Four original video animation episodes will be released in the last two BD/DVD volumes on June 27, 2011 for volume seven and July 27, 2011 for volume eight. The BD/DVD exclusive episodes will feature a break in the original story arc starting at episode 11 and offer an alternate ending from the TV broadcast. The anime retains the voice cast from the drama CD. Aniplex USA began streaming and simulcasting the series in North America through Anime News Network (ANN), but security issues involving the illegal leaking of episode two online resulted in the stream being placed on hold. The stream of Oreimo returned to ANN with the first four episodes on November 8, 2010. The opening theme for the anime is "Irony" sung by ClariS and composed by Kz of Livetune, while each episode features a different ending theme sung by one of the voice actors. The music of the anime is composed by Satoru Kōsaki and a soundtrack will be released on January 12, 2011.


 * Ending themes:
 * 1) "Little Sister, Plea~se!" (妹プリ〜ズ!) by Ayana Taketatsu
 * 2) "Shine!" by Ayana Taketatsu
 * 3) "Horaism" (ほらいずむ) by Ayana Taketatsu
 * 4) "White Heart" (白いココロ) by Saori Hayami
 * 5) "Orange" (オレンジ) by Ayana Taketatsu
 * 6) "Forelocks☆" (マエガミ☆) by Satomi Satō
 * 7) "Masquerade!" by Kana Hanazawa
 * 8) "Chameleon Daughter" (カメレオンドーター) by Hitomi Nabatame
 * 9) "'Cause I Love You!" (好きなんだもん!) by Ayana Taketatsu
 * "No, Tom Has Learned Sexual Arousal for His Little Sister" (いいえ、トムは妹に対して性的な興奮をおぼえています) by Yukari Tamura
 * 1) "Akihabara Dance Now!!" (アキハバラ☆だんす☆なう!!) by Ayana Taketatsu, Kana Hanazawa and Hitomi Nabatame
 * 2) "I'm Home." (ただいま.) by Ayana Taketatsu

Visual novel
A PlayStation Portable visual novel titled Ore no Imōto ga Konna ni Kawaii Wake ga Nai Portable is developed by Bandai Namco Games and will be released on January 27, 2011. The limited edition bundle will include an OAD, a sister-talk bonus CD, and an additional game for the PSP.

Reception
The Mainichi Shimbun reported that the fourth volume as the light novel which sold the most copies in August 2009. Anime News Network reported in April 2010 that the first five light novels have sold collectively 920,000 copies in Japan.