Oniichan no Koto Nanka Zenzen Suki Janain Dakara ne!!

Nao Takanashi is an ordinary junior high school girl who -- title notwithstanding -- really likes her older brother Shuusuke (though he is unaware of this), who turns out to feel the same for her, but manages to hold himself back out of respect for their relationship.

One day, whilst purging her brother's Porn Stash of anything not related to Brother-Sister Incest, Nao comes upon a family photo album full of childhood photos of Shuusuke and a girl in pigtails, but without her. When she confronts her parents, they tell her the truth: ten years prior, their close friends perished in a car accident, leaving Nao, their daughter, the sole (albeit amnesiac) survivor. But instead of angsting over the fact that she and Shuusuke are Not Blood Siblings, she's elated that she can finally pursue a full-fledged relationship with him. However, a blonde girl in pigtails appears shortly thereafter... and all hell breaks loose.

Oniichan no Koto Nanka Zenzen Suki ja Nai Dakara ne!! ("I Don't Like You at All, Big Brother!!") is a romantic comedy manga by Kusano Kouichi that started in 2008 with an anime adaptation for the Winter 2011 Anime block.

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Tropes used in Oniichan no Koto Nanka Zenzen Suki Janain Dakara ne!! include:

• A-Cup Angst: Nao, when she notices the bust size of Hirorin, Haruka and Kondou.
• A Date with Rosie Palms: According to Iroha, Shuusuke uses his left hand, and five times a day on average.
• A Day in the Limelight: Episode 7 focuses on the AGE explorers, rather than just Shuusuke.
• All Men Are Perverts: The members of the AGE (All Genre Ero), as well as Shuusuke's father.
  • On the female side, we have Nao and Iroha.
• All Women are Doms, All Men are Subs: Shuuske and his father.
• Animal Motif: Baby penguin versus Cat.
• Beach Episode: Early on, of course. Chapter 3/Episode 4.
• Bishonen: Captain Kirishima of the AGE.
• Blackmail: Kondou threatens Shuusuke with telling Nao of his Porn Stash after he rips off her yaoi magazines. Then again, that's a moot point, considering the kind of girl Nao is.
• Blank White Eyes: All over the place.
• Blonde, Brunette, Redhead: Iroha, Kondou, and Nao, respectively.
• Blue with Shock
• Brother-Sister Incest: Nao and Shuusuke, natch. Justifiable, since they're Not Blood Siblings, and Japanese laws allow for marriage between siblings by adoption.
• Butt Monkey: Shuusuke just can't catch a break
• Caught with Your Pants Down: Shuusuke was completely nonplussed when Iroha told him how much he masturbates (five times a day!), down to which hand he uses. It turned out she snooped him through a telescope.
• Censor Box: A baby penguin for Nao, as well as a cat for Iroha (both of which become their Animal Motifs). Strangely, like in Rosario+Vampire the censor boxes seem to be used almost entirely at random, which is especially strange considering that Nao provides an extreme close-up, uncensored Panty Shot in the opening of every episode.
• Cheryl Blossom: Kondou.
• Childhood Marriage Promise: Iroha gets this from Shuusuke in exchange for Playing Doctor with him. Shuusuke didn't think she was serious.
• Class Representative: Kondou.
• Clingy Jealous Girl: Iroha fits this to a T. Nao is this especially towards to the former.
• Color Failure
• CPR: Clean, Pretty, Reliable: Unfortunately for Shuusuke it wasn't a girl.
• Curtains Match the Window: Most everyone except Kondou and Iroha.
• Date Peepers: Nao does this during Shuusuke's date with Iroha; and later Those Two Girls peep on them. Taken to hilarious extremes in episode 3 of the anime when the AGE group shows up and spies on them, too.
• Different As Night and Day: Ran and Rin.
• Dissonant Serenity: Put Nao and Iroha in the same room together.
  • Add Kondou and it gets even worse.
• Double Standard Rape (Female on Male): Averted—Shuusuke is rather traumatized when he's forcibly french-kissed and molested by Iroha.
• Enemy Mine: Nao and Iroha team up once Kondou starts commanding most of Shuusuke's attention
• Erotic Eating: Episode 9.
• Fan Disservice: Unless you're into BL/yaoi scenes.
• Fan Service: quite a lot, especially from Nao.
• Festival Episode: Episode 9.
• First Episode Spoiler: Nao is adopted and is the sole survivor of a car crash that killed her parents, who happen to be Shuusuke's parents' friends.
• Fourth Wall Portrait: a variation. Kuro-neesan insists that Nao has "wonderful lips". We'll have to take her word for it.
• Funny Background Event: In episode 10 it has Mr. X/Kondou running to the store and back.
• Girlish Pigtails: Iroha
• Godiva Hair: Rin
• Gratuitous English: In the second episode: Kurosaki tells Shusuke to "Come and Join Us"
  • And Shuusuke replies with "Let's begin."
  • The OP is filled with very strange, hard-to-hear examples. "It's not vice!" "Please teach me sweet sunshine kiss!"
• Harem Series
• Hartman Hips: Drawing style permits this. Especially Nao.
• Heroic BSOD: In Chapter 2, Nao has one (at first) when she finds out that her and Onii-chan are Not Blood Related.
• Hey, It's That Voice!:
  • Saya is now the perverted little sister of Mikado Ryuugamine, and Beatrice is their mother.
    • Speaking of Eri Kitamura, it seems Yui has gotten a whole lot more perverted...
  • Yoko shows up as a sex-crazed childhood friend of Shuusuke's.
• Hot Mom: Shuusuke's mom is very easy on the eyes.
• Hypocrite: Nao and Iroha both accuses each other of this.
  • Nao was puzzled by Yamashiro's little stepsister fetish.
• Idiot Hair: Nao sports it.
• Laser-Guided Karma: Rin stalks Nao, and later forcefully kisses Iroha and then abducts her.
• Leaning on the Fourth Wall: The conversation in the anime/manga shop in Episode 7 could easily be about the show itself and its presumed audience.
• Likes Older Women: Kurosaki of the AGE.
• Younger Sibling Fetishization: Nao
• Love Makes You Crazy: Iroha
• Meganekko: Iroha, when she's not sporting her twintails.
• Mistaken for Gay: Well, that's what Shuusuke gets for buying BL magazines. Not like he had much choice in the matter.
• Modesty Towel: Subverted hardcore in Chapter 1/Episode 1.
• Mundane Made Awesome: Shuusuke's ultra high speed glancing look.
• My God, What Have I Done?: Shuusuke has this reaction when he realizes that his past perversions have made Iroha what she has become today, and even tries to make a complete turnaround on his lifestyle. Not that it sticks thanks to both Nao and Iroha. He gets over it.
• Naughty Tentacles: Episode 4, during one of Shuusuke's dreams.
• Non Indicative Title: Oh, sure, "I Don't Like You at All"?
• Not Blood Siblings: So Nao is now free to obsess about her big brother!
• Older Than They Look: A lot of the female characters.
• Only Sane Man: Haruka of Those Two Girls.
• Overly Long Title: Damn horribly straight to the point where it was shortened by fans as "Onichan no Koto". Anime eyecatches split the title into three lines.
• Panty Shot: In the manga especially.

"That panty-shot is pointless!"

• Patient Childhood Love Interest: Subverted—Iroha is not very patient.
• Playing Doctor: That's how Shunsuke winds up getting a Childhood Marriage Promise with Iroha.
• Princess Curls: Rin and Ran.
• Porn Stash: Shusuke's is of epic proportions.
• Promotion To Title Page: Kondou
• Proper Tights With Skirt: Kondou
• Psycho Lesbian: Rin "Clone" Yatagai towards Nao. But ends up kissing Iroha and falls in love with her instead, much to Iroha's horror.
• Rape Is Love: Iroha is more than willing to attempt this on Shuusuke because of their marriage promise.
  • It comes back to haunt her in the form of Rin.
• Rapunzel Hair: Iroha and Haruka and Hirono.
• Serious Business: Kondou and her Yaoi.
• Shout-Out: When the AGE goes to Akihabara, we see posters for Kiss×Sis, Yosuga no Sora and Chu-Bra, the anime adaptations of which, like this series, were produced by Starchild.
  • Ran's fantasy plot has a lot of Star Wars elements in it. From Ran's dress and nickname "Leila".
  • In episode 10 there was a Masou-Shoujo cosplayer.
• Something Else Also Rises: Chapter 2. Did you really think this kind of manga could go more than one chapter without it?
• Stalker with a Crush: Nao knows when Shuusuke learned to collect, read and hide his porn. The stuff Iroha's done is too long to list here.

"Shuusuke doesn't have any privacy does he?"

• Stealth Pun: May or may not be intentional, but often, the Censor Box... for English-speaking audiences, anyway.
• Strange Twins: Rin and Ran.
• Suspiciously Specific Denial: No, Shuusuke's father doesn't find his S&M porn one bit erotic.
  • The title of the manga itself, too.
• Tall, Dark and Bishoujo: Haruka, Kondou and Rin.
• This Loser Is You: The AGE, taken to fourth-wall leaning levels on their trip to Akihabara.
• Those Two Girls : Haruka and Hirono
  • Also those three guys of the AGE.
• Title Drop: at the very end.
• Too Hot for TV
• Too Soon: Tsunami scene on the school rooftop in Episode 10. GIF here, viewer discretion advised
• Tsundere: Nao play-acts this when she believes Shuusuke has had enough Fan Service.
  • The title of the series as well.
• Victorious Childhood Friend: Captain Kirishima wants to have one.
  • Also, Iroha is determined to become one.
• Visual Innuendo: Everything at the festival in Episode 9, including fireworks symbolizing orgasm. Then the joke is made obvious at the end of the episode, implying that earlier Nao had climaxed at Shuusuke's touch.
• Yandere/Clingy Jealous Girl: Nao and Iroha. The two are pleasant on the surface, but by chapter 12... well...
  • Rin's Fangirls
• Yaoi Fangirl: Kondou
• Zettai Ryouiki: Nao and sometimes Iroha.