Little Sister Heroine
"The whole 'little sister' thing is the fantasy of guys who don't have sisters in real life."The Little Sister Heroine is a trope common in multiple Japanese media that combines the idea that little sisters are cute and that cute things are to be fetishized. It goes like this: Little sisters are cute, right? And cute girls draw in viewers. And cute can be sexy. Take a few more 'logical' steps down the line, and suddenly little sisters are love interests in anime, video games and visual novels. It is in fact one of the most popular types of heroine or love interest in Visual Novels, branching out from there into anime, perhaps surpassed only by the ever-present tsundere and childhood friend. Like the similarly ubiquitous Childhood Friend Romance, it is extremely prone to lampshade hangings. As a Love Interest trope based on the little sister/older brother dynamic, the story will usually dwell on the romantic tension between them, though the brother may be completely oblivious. Despite the name, Little Sister Heroine attempts to mitigate the obvious incestuous fallout; they're usually either a step sister, adopted or, more rarely, technically a cousin or distant relation. In almost all cases, the younger sister is going to be either some degree of tsundere, childish and clingy, or simply highly devoted to their older brother. Finally, the relationship between the two will likely be noticed or exaggerated by the rest of the cast. If you don't notice at least several of these general characteristics, it's probably not this trope. It rarely works like this in real life. Those who have younger sisters themselves and hear about this trope often claim that they're annoying rather than cute, making this trope more wish fulfilment than anything like an accurate portrayal of sibling dynamics. Thanks to the Westermarck effect, it is far more likely that the idea of any kind of romance with your sister would be either laughable or even outright disgusting. Also known in some circles as an imouto heroine. See also Brother-Sister Incest and Flirty Stepsiblings. May overlap with Big Brother Attraction, Big Brother Mentor, Big Brother Instinct, and usually will with Not Blood Related.
— Koyomi, Bakemonogatari
- The premise of Oreimo is largely based around this trope. Kirino plays games with this trope as their focus and is the tsundere type herself. The relationship between her and her older brother Kyousuke is probably the biggest focus of the series.
- The World God Only Knows has Keima absolutely refuse to acknowledge that Elsie is a proper little sister because she doesn't match the template from his beloved gal games. Eventually, however, he decides to acknowledge her, but only because he wants to get their contract completed quickly. As time goes on, she eventually really does become his little sister, moving away from this trope in the process.
- Kara no Kyoukai has Kokutou's little sister Azaka. She has an inherent interest and draw towards things that are taboo, so she develops an incestuous crush on her brother. Azaka is the template for Akiha in Tsukihime.
- Yosuga no Sora has Sora, the main character's twin little sister. She has very strong feelings for her brother, going as far as thinking of him during... certain private times.
- A justification is attempted by showing, in a flashback, that Sora spent most of her childhood hospitalized, and so Sora and Haruka didn't spend enough time together for the Westermarck effect to kick in. Why Haruka was kept away from his sister for so long is never explained.
- Kureha of Mayo Chiki! is a member of Jirou's Unwanted and Supporting Harem. Observe her reaction upon finding that Jirou, who has gynophobianote may have a girl over at the house. It's not ignoring something that's none of her business, or happiness that her brother has finally gotten over the condition that has crippled his social life, but rather to kick down doors and scream:
Kureha: Who's been swindling my brother!?
- Parodied in Dokkoida?!, where the main character lives with an alien girl masquerading as his little sister. Thanks to a soap opera episode following this trope, she and the majority of their neighbors (who are also aliens) become convinced that it applies to the main character as well, thanks in part to Dirty Old Man Dr. Marronflower using his own library of H-games as evidence. Hilarity Ensues when the two who have a crush on the hero attempt to invoke it to their advantage, leaving him completely confused.
- Nao from Onii-chan no Koto Nanka Zenzen Suki Janain Dakara ne!!, whose life goal is to hook up with her adopted brother Shuusuke.
- Taken to a whole new (hilarious) level in Nisemonogatari with Araragi's little sisters, Karen and Tsukihi. That infamous toothbrushing scene.
- In Date A Live, Kotori Itsuka is a parody of this when first introduced. Her foster brother Shido (and others) even call her his "cute little sister". It then gets subverted when we meet her other personality. The romantic subtext is unclear. She is implied to have some not-quite-sisterly feelings for her brother, but doesn't have a problem setting him up with the Girl of the Week (It Makes Sense in Context). The only time she goes into Clingy Jealous Girl mode is when she meets his biological sister, Mana, at which point she reveals the level of her interest in him by arguing about who's better and finally declaring that not having any real relation is better because a real sister couldn't ever marry him.
- As with many other tropes in Genshiken, this one is raised and then shot down.
- Enju Ahiara from Black Bullet is seen as this from Rentaro's perspective. This can be a deconstruction of this trope, as Enju's Precocious Crush moments not only serves as a annoyance to Rentaro, but Enju's high corrosion rate and the fact that she's slowly turning into a Gastrea serves as an emotional burden to him.
- Sket Dance have Saya, a redheaded tsundere with large breasts and twintails. Bossun and Switch remarked that she looks exactly like a Visual Novel character, and is only missing the "little sister element". Turns out she is actually the younger sister of another recurring character, i.e. student council president Agata.
- Chino in Is the Order a Rabbit? is being seen by many of the cast as one, to her annoyance.
- Brothers Conflict has this as its premise, with all of the stepbrothers going after the little sister from the point of view of the "Little Sister" herself. (Makes some sort of sense, as it is based off of an Otome game
- Eien no Aselia has Kaori, but in the end she turns out to be more of a Living MacGuffin than a heroine and does not even have a proper ending. Yuuto is frequently accused of being a siscon due to his overprotective nature, but in the end it turns out to work in reverse due to her unrequited affections.
- Men at Work 2 has Mena as a possible love interest, though not the main one.
- Persona 4 has The Protagonist's cousin Nanako Doujima, who refers to him as "Big Bro" and gains a Precocious Crush on him at the end of her social link. Nothing gets made of it, unless the player also maxes out her father's social link, in which case his only protest is that Nanako is still too young.
- Parodied with Desco◊ in Disgaea 4: A Promise Unforgotten. Desco was created specifically to fulfill Fuka's childhood wish for a little sister, and as such was implanted with all of the classic traits of a Little Sister Heroine. However, since Fuka is an eccentric individual who wished for her Little Sister Heroine to come with "advanced functioning to help me take over the world," Desco was also created with Lovecraftian Superpowers and a compulsion for complete annihilation. The result is the world's most Adorable Abomination.
- Disgaea Dimension 2 gives us a straighter example with Sicily, Laharl's Long Lost Sibling. While she naturally plays the trope straight, she tries to really invoke it for all it's worth by playing up her cuteness and offering sweets to convince Laharl to give up the title of Overlord. It only serves to further piss him off.
- Ar Tonelico 2: Cocona is Croix's adoptive sister and very cute. She confides in Cloche that she is in love with him but his only love is as a brother because of their age difference, though if you don't secure any of the other three endings you default to her. The sequel suggests that this is the true ending, however.
- Mia in Duel Savior Destiny is definitely the Clingy Jealous Girl type with some level of tsuntsun going on. Her actual degree of relation to Taiga gets retconned, though. In the epilogue of her route, it's hastily claimed that it sure is convenient that they're not related. In the final route, it turns out they actually do share a blood relation and are probably half siblings.
- In Fire Emblem Fates, Princess Sakura of Hoshido and Princess Elise of Nohr follow the archetype. Each girl is the youngest of the local Royal Families (Sakura is the Avatar's blood-related sister only not while Elise is the adoptive sister kind), both adore the Avatar in her own ways, and both will be heartbroken if the Avatar doesn't join the side she supports.
- A non-Japanese example from a Western developer that likes playing with JRPG tropes: Bethany Hawke from Dragon Age II hits almost every note of this trope. Young? Check. Cute? Check. Needs rescuing from time to time? Check. Adores her older sibling? Double check! Romanceable? Nope.
- Another non-Japanese example: Luxanna Crownguard AKA Lux from League of Legends. She is the little sister of Garen, a distant one, and a Cute Witch that serves the nation of Demacia well, just like her big bro. And while she certainly have some things to call out on him, she clearly respects him a lot. She's in about her teens, and so far she seems to be hooking up with another champion, Ezreal. But that doesn't stop Fanon to think that Garen may not want to hand his sister over that easily to Ezreal.
- Noel Vermilion of Blazblue. Kind of a Zig Zagged Trope because she's not actually Ragna's little sister but rather a clone of her. But still, everything else about the trope is played straight. Its heavily implied she has a crush on him, and even if she doesn't, she looks up to him like an actual older brother and the normally withdrawn and antisocial Ragna is fiercely protective of her. Their relationship is a major focus of the series at that.
- Akiha in Tsukihime is largely written around this. Unfortunately for her, except for in her own ending this means she never graduates from 'little sister', even in sequels and expanded universe material. A definite tsundere type, she's even called Imouto (Little Sister) by Arcueid rather than her actual name.
- Nemu in Da Capo, where she's even the main heroine. In a rare case of not being completely Oblivious to Love, Junichi is in fact perfectly aware of how she feels but isn't quite comfortable with a relationship upgrade. Nemu is quite the tsundere and very clingy.
- Da Capo II actually has two adoptive sister figures, but the one who plays it up more is Yume, who is younger than Yoshiyuki. Yume, a clear Nemu expy, is in general less clingy. Everyone at their school seems to be jealous of Yoshiyuki having such a cute little sister despite his frequent claims that there's nothing between them.
- Canvas 2 has Ellis, though she's actually his cousin. She tends to be extremely clingy and childish.
- G-Senjou no Maou has Kanon. Not only is she a heroine, but Kyousuke appears to be the only person she actually trusts. Kyousuke himself lampshades the romantic overtones of the trope, but doesn't appear to take it seriously until she confronts him about it halfway through the main storyline, at which point her own miniroute splits off.
- Suika subverts the general trend of the little sister being a heroine when Akane stabs her stepbrother to death should he choose her. She's actually in love with his fiancée, so choosing her means that Akane feels that it's okay to take his place and brainwashes his fiancée accordingly.
- In Family Project, Matsuri eventually moves in to a little sister position for Tsukasa, even adopting the Japanese Sibling Terminology. Her route, however, tends to focus on the fact that she's far younger than he is.
- Kara no Shoujo has Yukari, but despite the Brother-Sister Incest all over the story, you cannot sleep with her. The very idea clearly would not occur to Reiji.
- She does have a topless CG though.
- Fate/hollow ataraxia as a general sequel to Fate/stay night that contains all of its continuity has open acknowledgement of Ilya as Shirou's little sister, a relationship set up in several endings. And she really exploits it too: She's clingy to the point of nearly picking up her former yandere traits and tends to act her apparent age rather than her real age. She still gets no adult scenes, though, despite being the closest thing the series has to a fourth heroine. Also, worth pointing out the two aren't actually related. Shriou was adopted. She's also not really his little sister either, she's actually older than him. Its more invoked than anything.
- Yume Miru Kusuri has Aya, but her route was cut. It is strongly implied that she fell in love with Kouhei because he was always subtly out of place in their home, making it difficult for her to see him as her brother.
- Like the The World God Only Knows example above, Kouhei appears to be frustrated with her at one point for not being anything like the little sisters in H-games. "You're supposed to call me onii-san!" Aya is appropriately confused.
- Chaos;Head has Takumi and his little sister, Nanami. The way the game works means that as with the other female main characters, you can trigger certain 'delusion' events about her that occur only in Takumi's head, but that he doesn't control. Or something. Though it turns out that he's not Takumi. Exactly. It's complicated.
- Lampshaded with Rizu in A Profile.
Masayuki: I'm not marrying you. I want to make sure you don't fall for me or anything. We're only stepsiblings, so I thought I should make that clear.
- Kana: Little Sister has the main character's terminally ill little sister as the main heroine. The VN itself is possibly the Trope Codifier for this kind of relationship.
- Inverted in Crescendo, where the older sister (Ayame Sasaki) is the one who gets the path. And yes, she's very pretty too.
- The H-Game Imouto Paradise has a Themed Harem of no less than five little sisters, all of them different but adorable all the same.
- In the closing stages of World War II, Imperial Japan created the Chiran Nadeshiko (Ladies of Chiran) Units. A bunch of middle-school and highschool girls served as surrogate 'little sisters', providing housekeeping and company for transient pilots at Chiran Airbase in Kagoshima Prefecture, during the brief periods between their arrival from training bases elsewhere and their departure on their fatal missions. The unit was highly publicized at the time and may even be the Trope Codifier... but growing close to so many young men (some being almost the same age as them!) that were sent off to die in 'Kamikaze' attacks took its toll on the girls, so the project was ultimately pulled under the "Harmful to Minors" label. Their story can be found in books like BLOSSOMS IN THE WIND: Human Legacies of the Kamikaze, by M.G. Sheftall., or Tokkou no Machi: Chiran by Sanae Satou.