Characters

Kyosuke Kosaka (高坂 京介 Kōsaka Kyōsuke?)

Voiced by: Yuichi Nakamura, Mami Fujita (young)

Kyosuke 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 eroge and after he confronts her, he 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. After which, he promises to take up more of his role as an older brother to her. Despite this, she is generally the dominant person in their relationship, with Kyosuke being shown to be openly intimidated by her, only standing up to her in truly serious situations. Kyosuke initially claims to prefer to have a relatively peaceful and simple life, but grows to love spending time with his sister and enjoy the drama she causes to the point where he becomes lonely when she is not around. Kyosuke helped Ruri make friends and joins the Game Research Club with her during his third year when Ruri becomes his junior. Kyosuke dates Ruri during summer vacation until she breaks up with him. In the PSP game Ore no Imōto ga Konna ni Kawaii Wake ga Nai Portable ga Tsuzuku Wake ga Nai, Kyosuke is the son of his current mother's sibling.

In the past, Kyosuke had good grades and was the fastest runner in his elementary school. He also had the tendency to shoulder everything himself, thinking that there was nothing that he could not achieve, and often said "Leave it to me". However, Kyosuke was convinced by Manami that he should not try so hard at everything, which drastically changed his personality into someone who only desired to live a normal lifestyle, as his studies and athleticism worsened day by day.

Kirino Kosaka (高坂 桐乃 Kōsaka Kirino?)

Voiced by: Ayana Taketatsu

Kirino is Kyosuke's 14-year-old younger sister. She is normally mature and independent for her age in front of others, but her true personality is at times immature, abusive and ungrateful with an aggressive, tsundere-like personality. Mostly only to Kyosuke does Kirino show her much more intolerable personality, where she orders him to play her games and care for the characters, only to insist that 2D and 3D worlds should be kept separate and accuse him of being a pervert and a lolicon afterwards. She is secretly an otaku with an obsession for "little sister"-themed eroge, as well as the children's anime series Stardust Witch Meruru. She works as a magazine model and later becomes a novelist, the funds from which she uses to support her hobby. Despite her interests, she states she does not know why she started liking eroge and denies having a brother complex. Nevertheless, she frequently forces Kyosuke 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.

Kirino is also shown to become frustrated whenever Kyosuke is with or shows interest in other girls. She even goes as far as to sabotage his time with another girl, however despite this, she is genuinely grateful to her brother. Although she states that she only likes eroge because of their cute characters, she shows a perverted side of herself when playing those games. She uses the screen name Kiririn when with her otaku friends. She had admired Kyosuke in the past, who she had seen as a perfect brother. Kyosuke starts distancing himself from her during elementary school. Kirino once tried to chase Kyosuke and he ran away to play with his friends, but fell down and cried in disappointment, which spurred her to start working hard on her academics and sports. She was severely disappointed at Kyosuke's change in personality after the incident with Akimi.

Ayase Aragaki (新垣 あやせ Aragaki Ayase?)

Voiced by: Saori Hayami

Ayase is Kirino's classmate who works as a model alongside her and is also her best friend. She admired Kirino for being seemingly so perfect in every way, and she originally had a simple crush on Kyosuke, thinking of him as Kirino's caring brother. That all changes when she finds out about Kirino's otaku hobby and how Kyosuke was aware of it and helps support it. She is greatly disappointed in Kirino and Kyosuke at first, but later reconciles and tries to come to terms with at least Kirino, but not as much with Kyosuke. Ayase is normally a friendly, nice, and refined girl, but becomes agitated and somewhat violent at the thought that she is being lied to, which she hates above all else. She also has a tendency for prejudice, as she believes what she hears on the news, thus she disapproves of anime and manga, calling it a disgusting hobby, especially eroge, due to the media portrayal that otaku will eventually become criminals. Once she develops a dislike and contempt for someone, she shows a much ruder and even hostile side of herself. She stubbornly maintains a strong dislike and disrespect of Kyosuke, convincing herself that he is really the pervert she persistently calls him. She becomes good friends with Manami and often confides private matters to her. She eventually harbors romantic feelings for Kyosuke.

Manami Tamura (田村 麻奈実 Tamura Manami?)

Voiced by: Satomi Satō

Manami is Kyosuke's childhood friend. She wears glasses and is described as "plain", something she views as a compliment from Kyosuke. She has a crush on Kyosuke and blushes to his compliments. Due to the time they spend together, the people around them assume they are dating. Kyosuke explains that though he does not have any strong feelings for her beyond close friends, he does not like the idea of Manami having a boyfriend for some reason. Many times, he is unaware of Manami trying to become closer to him by trying to do things that couples do and how she is willingly doing things to please him in any way, such as cooking and cleaning. According to Kyosuke, her speech patterns resemble that of a grandmother or an old lady. Manami had in the past convinced Kyosuke to give up his personality to act tough and made him into the average person today, which severely disappointed Kirino, causing a rift between her and Kirino. She manages to make up with Kirino thanks to Kyosuke's help in getting them to talk. She later confesses to Kyousuke just to be rejected.

Saori Makishima (槇島 沙織 Makishima Saori?) / Saori Bajeena (沙織・バジーナ Saori Bajīna?)

Voiced by: Hitomi Nabatame

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 (her alias is named after the character, Quattro Bajeena) and is also a collector of their model kits. Despite her general appearance in public, Saori is actually 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 Kyosuke says, Saori is drastically different from how she communicates through the Internet and phone and speaking with her in person, to which she seemingly switches to a refined and sophisticated persona.

According to Kyosuke, she dresses as a stereotypical otaku, but has the body of a supermodel. Despite being a middle school girl around Kirino and Kuroneko's ages, she is around the same height as Kyosuke, which surprises him when he first meets her. Despite her cheery attitude, Saori is quite lonely, living by herself, and has always feared that one day her true friends (Kirino, Kyosuke, and Ruri) would leave her in a similar way that her older sister (who got married and moved away) left her. The reason she set up a hobby group is that she was, described by her sister, "just the sister of a member" in her sister's group Pretty Garden, and was severely disappointed and angry at her sister when the group eventually dissolved after her sister moved away.

Ruri Gokō (五更 瑠璃 Gokō Ruri?) / Kuroneko (黒猫?, lit. Black Cat)

Voiced by: Kana Hanazawa

Ruri is a 15-year-old otaku girl who lives near Kirino and later enrolls into Kyosuke's school. She 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. However, both girls genuinely care for each other and value the time they spend together. Kuroneko is very prideful like Kirino, but is willing to swallow her pride to achieve a goal. Unlike Kirino who likes little sister-themed games and magical girl anime, Kuroneko enjoys teen-centered fantasy anime. She often mentions "dark magic", claiming that she has it. She is noted to have a very large vocabulary, to where Kirino comments she needed to use a dictionary to translate her novel. Kuroneko actually wears red contact lenses to make her bluish eyes appear red.

Kuroneko has two younger sisters, Hinata and Tamaki, whom she dearly cares for, though her sisters and mother worry about Ruri when she is in her otaku mode. At school, Kuroneko wears normal clothes and at home takes care of her younger sisters. She later joins the video game club after she enrolls into Kyosuke's school; she is very good at playing video games. She dates Kyosuke for over summer vacation before breaking up with him. However, she still harbors feelings for Kyosuke. Kyosuke later rejects her feelings and she accepts that they will not be together.

Kanako Kurusu (来栖 加奈子 Kurusu Kanako?)

Voiced by: Yukari Tamura

Kanako is Kirino and Ayase's fellow friend, classmate and model, who sometimes swaps between a cute personality to a bratty one. She is a talented singer who dreams of becoming an idol, often going to a lot of auditions. Since she goes to karaoke places frequently, she is capable of remembering any song she has heard at least once perfectly. 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 and wins. Despite winning the contest, she is disgusted of what she had gone through, but likes the idea of being praised and the event even helps her career. She later realizes the fact that Kyosuke, who acted as her manager, is Kirino's brother. She also asked Manami to teach her cooking in order to be able to cook for her parents.

Daisuke Kosaka (高坂 大介 Kōsaka Daisuke?)

Voiced by: Fumihiko Tachiki

He is Kirino and Kyosuke'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 eroge, although Kyosuke manages to successfully protect even the eroge by claiming they belong to him. 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 claims that he knows best of what is going on in the family and he has always known that the eroges belonged to Kirino, despite Kyosuke's effort to convince him otherwise. In Ore no Imōto ga Konna ni Kawaii Wake ga Nai Portable ga Tsuzuku Wake ga Nai, he is Kyosuke's uncle.

Yoshino Kosaka (高坂 佳乃 Kōsaka Yoshino?)

Voiced by: Akeno Watanabe

She is Kirino and Kyosuke's loving mother. She is aware of her daughter's obsession, as she has referred to her as "my otaku daughter". She is aware of many things going on in her family and helps keep the peace in the house. She is the first one to question the improving relationship between Kyosuke and Kirino, which in turn resulted in Kyosuke moving out in order to prepare for his examinations. However, she never doubted Kyosuke and Kirino to be in an unhealthy relationship and was instead using this improved relationship in order to improve Kyosuke's grades. In Ore no Imōto ga Konna ni Kawaii Wake ga Nai Portable ga Tsuzuku Wake ga Nai, she is Kyosuke's aunt.

Iwao Tamura (田村 いわお Tamura Iwao?)

Voiced by: Hiromi Ohtsuda

Manami's little brother, whose attempts to follow the cool trends often backfire on him. He sports a buzzcut having been convinced he was getting a skinhead look. It is hinted that he formed a pact with Kirino during primary school to boycott Kyosuke and Manami, but apologized to Kyosuke after he was helped by Kyosuke in school and is since then a loyal follower of Kyosuke.

Kōhei Akagi (赤城 浩平 Akagi Kōhei?)

Voiced by: Junji Majima

Kyosuke's classmate who, similar to Kyosuke, often has to support his little sister's hobby for eroge. Though unlike Kyosuke's strained relationship with Kirino, Kōhei's relationship with Sena is much better, but Kyosuke considers him somewhat of a siscon. While he is a huge siscon, his feelings for his little sister are completely unromantic and only loves her as a little sister.

Gennosuke Miura (三浦 絃之介 Miura Gennosuke?)

Voiced by: Go Inoue

The president of the Games Research club at Kyosuke's school, which both Kyosuke and Ruri end up joining. He is also into little sister-themed eroge, as Kyosuke first meets him when trying to borrow a bike to ride home following a midnight eroge launch.

Sena Akagi (赤城 瀬菜 Akagi Sena?)

Voiced by: Mariya Ise

Kōhei's little sister and a member of the Games Research club, as well as Ruri's classmate. Similar to Kirino, she has an obsession with eroges, albeit she prefers the hardcore yaoi genre to an extent that she will even fantasies about her other clubmates, pairing her brother and Kyosuke as a couple and becoming visibly disappointed when Kyosuke assured her that he was straight. The relationship she has with her brother is quite strong yet it is unclear how they feel about each other. She joined the Games Research club in order to learn how to become a games designer. She is also very good at games, having the high score before Ruri beat it. This also attributes to her skill in programming, being able to debug very easily. In volume 12, she ends up dating Makabe.

Kaede Makabe (真壁 楓 Makabe Kaede?)

Voiced by: Yoshitsugu Matsuoka

Kaede is a second year member of the Games Research club, and also the most normal member of the club. Dates Sena in volume 12 and calls Kōhei "Aniki".

Iori Fate Setsuna (伊織・フェイト・刹那 Iori Feito Setsuna?)

Voiced by: Shizuka Itō

Iori is the editor who published Kirino's work. In the Light Novel, she stole Kirino's work and posted it as her own.

Misaki Fujima (藤真 美咲 Fujima Misaki?)

Voiced by: Yū Asakawa

Misaki is the president of Eternal Blue who tried to persuade Kirino to pursue a modelling career abroad.

Kōki Mikagami (御鏡 光輝 Mikagami Kōki?)

Voiced by: Yūichi Iguchi

Kōki is a model who is secretly an otaku. He was requested by Kirino to be her fake boyfriend in order to make Kyousuke understand how she felt when he hung out with other girls. Later on, he befriends Kyosuke and helped him several times, such as giving dating advice. However, he also causes trouble for Kyosuke, such as when he gave Kyosuke an expensive set of adult game figures as a housewarming gift.

Hinata Gokō (五更 日向 Gokō Hinata?)

Voiced by: Kana Hanazawa

The elder one of Ruri's little sisters. Despite her young age, she is able to understand the situation her sister is in. She once had thought that her sister's boyfriend, Kyosuke, is a delusion her sister is having, and was surprised to find out that Kyosuke is real. She also understands the circumstances around Ruri's breakup with Kyosuke.

Tamaki Gokō (五更 珠希 Gokō Tamaki?)

Voiced by: Yui Ogura

The younger one of Ruri's little sisters. She was scared by Kirino's beastly act upon seeing her, due to Kirino's sister complex. She loves her older sisters dearly and gets along well with Kyousuke.

Bridget Evans (ブリジット・エヴァンス Burijitto Evuansu?)

Voiced by: Misaki Kuno

Bridget is the winner of the first Meruru cosplay event. However, she lost to Kanako in the second event. She later grew to be quite close to Kanako.

Ria Hagry (リア・ハグリィ Ria Haguryi?)

Voiced by: Ibuki Kido

Ria is Kirino's roommate during her stay in The United States who devotes all her life to running. Dubbed as the fastest elementary school runner. Kirino outran her once when Kyosuke came to pick Kirino up in The United States. Ria came to Japan seeking revenge, and successfully did so, as well as find out how Kirino got so fast.

Kaori Makishima (槇島 香織 Makishima Kaori?)

Voiced by: Houko Kuwashima

Kaori is Saori's elder sister who created the group Pretty Garden, which Saori participates in. However, she left a bad impression on Saori as she left for America, which caused Pretty Garden to dissolve, to Saori's dismay, and eventually influenced Saori to create her own hobby group. It is revealed that after the misunderstandings between the sisters was solved, they became close.

Kanata Kurusu (来栖 彼方 Kurusu Kanata?)

Voiced by: Rie Kugimiya

Kanata is Kanako's sister. A manga author who is a prominent member of Pretty Garden. She is Saori's biggest influence in her otaku hobbies.

Shinya Sanada (真田 信也 Sanada Shinya?)

Voiced by: Masayuki Katō

Shinya is another prominent member of Pretty Garden.

Sayaka Kakei (筧 沙也加 Kakei Sayaka?)

Sayaka is the owner of Ayase's fan blog who stalks Ayase. Sayaka admires Ayase, and was disappointed in the misunderstanding that Ayase started dating Kyosuke as Ayase went to Kyosuke's house every day during his mock-exam period. Kyosuke eventually mediated the relationship between Sayaka and Ayase while Sayaka said that she aspires to be a photographer.

Akimi Sakurai (櫻井 秋美 Sakurai Akimi?)

Voiced by: Ayane Sakura

Akimi is Kyosuke's middle school classmate who refused to come to school during middle school. After several attempts, Kyosuke managed to convince her to come to school and even forged her parent's signature in order to bring her on a field trip. However, during the trip, Akimi was injured after falling from a tree in a restricted area Kyosuke brought her to. As a result, her parents moved her to another school and forbade Kyosuke from interacting with her again, which was the main cause for Kyosuke's change in personality. 3 years after the incident, Akimi managed to find Kyosuke and confessed to him, but was rejected.