A Sister's All You Need

A Sister's All You Need (Imōto Sae Ireba Ii.) is a light novel series that began in 2015. It was made into two manga series in 2016-2018, and an anime in 2017.

Itsuki Hashima is a light novel writer who, to be short, writes very weird fiction, to not mention inconsistent - to the point his editor gets incredibly mad at his new manuscript and rejects it. The thing is, Itsuki is madly obsessed with the concept of having a little sister and not in a normal way. His editor presumes that happens because he don't have a little sister, but instead just a cute little brother. But then again, maybe he don't would have a career if he didn't.

Despite his creepy behaviour, Itsuki still attracts the attention of one girl who admires his writing: Nayuta Kani, a girl who seems to obsessed about sex and dirty jokes.

Written by Yomi Hirasaka and illustrated by Kantoku. Published by Shogakukan.

Tropes used in A Sister's All You Need include:

• Brother-Sister Incest: Itsuki is obsessed with it to an unhealthy level. Almost all of his novels feature little sister heroines and the one where the little sister isn't the heroine, the heroine is out of focus exactly in favour of the little sister.
• Censor Steam: In the opening scene of the anime, that's the only thing preventing the audience of seeing a female character's breasts.
• Double Entendre: In Episode 4 of the anime, Haruto jokes about Itsuki wanting a liquid coming from a hard black thing flowing down his throat. He's talking about a bottle of gin.
• Dude Looks Like a Lady: Itsuki's younger stepbrother looks a little too much like a girl.
• Erotic Eating: Trying to seduce Itsuki, Nayuta eats an egg on sticks he offers to her in the most titillating way she can think of.
• Exactly What It Says on the Tin: Itsuki owns an Eroge called "A Little Sister Who Loves Her Brother, And That Masturbates Every Day Using His Underpants". It's exactly about that as Itsuki explains after Ashley asks what is about.
• Failed a Spot Check: Itsuki was disappointed by a game not being about a little sister despites the title already saying she is dead from the beginning.
• Flower in Her Hair: Ashley Oono has a red flower on the left side of her hair.
• Girl-On-Girl Is Hot: Inverted. Nayuta is excited by the idea of two boys "going at it".
• Mood Whiplash: A emotional scene about Miyako's past is suddenly followed by Nayu splashing her face with water and the two having a funny water fight.
• Most Writers Are Writers: A light novel about light novel writers.
• Ms. Fanservice: Nayu isn't only beautiful and curvaceous as she as perverted as possible. Making fanservice happen is her way of attracting Itsuki.
• Naked People Are Funny:
  • In episode 2 of the anime, Itsuki is caught several times by his friends naked. It don't helps the second time he goes to the door with only a towel covering her body, and then let it fall.
  • Nayuta writes while naked.
• Older Than She Looks: Ashley is 32 years old, but looks not much older than Nayu, who is said to be 18.
• Scenery Censor: To prevent us of seeing Nayuta's "assets" in their full glory.
• Skewed Priorities: Ashley only seems to care about the ways she can cut Itsuki's taxes, even asking for him to write lines in a way she can say he was spending money on something it was "research" for his work, completely disregarding how stupid that would be. Remember the whole reason she has a job with Itsuki is because he is a good light novel writer.
• The Beard: Inverted. Haruto is trying to appear more gay to not make people suspicious about him possibly dating VAs of shows adapted of his light novels, so he takes photos of him having dinner with Itsuki and his little brother to look "fagger".
• The Corrupter: Ashley at least wants to be one of these. Is just that in her case the evil is tax fraud.
• Yandere: There's nobody for Nayu to be jealous of though; she is just crazy obsessed with Itsuki, but he rejects her.