History Main / MySisterIsOffLimits

* ''[[Fanfic/MyDeepestDarkestSecret 𝕸𝖞 𝕯𝖊𝖊𝖕𝖊𝖘𝖙, 𝕯𝖆𝖗𝖐𝖊𝖘𝖙 𝕾𝖊𝖈𝖗𝖊𝖙]]'': [[GenderInvertedTrope Well, brother, actually]]. It's mentioned that the vampires often scare off any admirers of Solon. Solon recalls a time seeing Jino, ''[[BewareTheNiceOnes of all people]]'', burn a bunch of love letters meant for him during Valentine's Day. Solon didn't even meet the wolves until the time of the story because a few years ago, they ''stared at him for a few seconds'' and they thought they were ogling him. Kind of {{justified}}, given that the people Solon tends to attract can either be a good or bad person, and the complicated nature of people makes it hard for them to tell which is which. [[spoiler: Luckily, aside from intense interrogating, Enzy didn't suffer when they found about his and Solon's [[OfficialCouple relationship]], and they even let them stay together]].

->''"GET OFF MY SISTER!"''
-->-- '''Ross''' finding out Monica and Chandler are sleeping together, ''Series/{{Friends}}'', "The One Where Everybody Finds Out"

* ComicBook/SpiderGirl is a rare female example of this trope, trying her to keep her [[CloningBlues "little sister" April]] away from her manipulative JerkJock ex-boyfriend.

In the original Franchise/{{Dragonlance}} trilogy, boyhood best friends Tanis and Gilthanas fell out over the former's romance with Gilthanas's younger sister. Tanis is a half-breed and a bastard, while Gilthanas and his sister Laurana are a royal prince and princess, and thus Tanis is considered unworthy of her.

** Steven, conversely, tells Jeremiah Belly is off limits to Conrad (by extension, him as well). He accepts it reluctantly one's he's discovered their relationship however.

* ''LightNovel/{{Oreimo}}'':

* ''LightNovel/ThePetGirlOfSakurasou'':

* ''Film/ThirtyMinutesOrLess'', among other things'', has the protagonist reveal to his best friend that he has slept with his twin sister. The friend is pissed, as he reasons that sleeping with one twin is the same as sleeping with the other.

-->'''Quagmire:''' ''(to Brian)'' If I ever see you anywhere near by house again, '''''I'll blow your head off!''''' ''(delivers a few more punches before leaving)'' Now lay there and die, you piece of crap!

* Among some traditional people, like the Maasai in East Africa, it is common for young men of the same age to form a group of warriors. They consider the others in the group their brothers and hence, dating a "brother's" sister is considered incest and as unthinkable as dating your own. (Most traditional societies take social relatedness very seriously. For example, there is such a thing as milk siblings -- having been breastfed by the same woman makes people siblings, which makes sense if you consider that having been raised together they will view each other as siblings, regardless of genetics.)

* Among some traditional people, like the Maasai in East Africa, it is common that young men of the same age to form a group of warriors. They consider the others in the group their brothers and hence, dating a "brother's" sister is considered incest and as unthinkable as dating your own. (Most traditional societies take social relatedness very seriously. For example, there is such a thing as milk siblings -- having been breastfed by the same woman makes people siblings, which makes sense if you consider that having been raised together they will view each other as siblings, regardless of genetics.)

* Among some traditional people, like the Maasai in East Africa, it is common that young men of the same age form a group of warriors. They consider the others in the group their brothers and hence, dating a "brother's" sister is as unthinkable as dating your own. (Most traditional societies take social relatedness very seriously. For example, there is such a thing as milk siblings -- having been breastfed by the same woman makes people siblings, which makes sense if you consider that having been raised together they will view each other as siblings, regardless of genetics.)

* Inverted in ''LightNovel/HighSchoolDXD''. Sirzechs is perhaps the most enthusiastic Issei/Rias shipper of the lot, in a series where even her [[HaremSeries eager harem-mates]] want to see them hook up.
* A reversed example in ''LightNovel/InfiniteStratos'': Chifuyu Orimura, possibly the world's strongest IS pilot, is very much aware of the UnwantedHarem that pines for her younger brother Ichika, but she makes it clear she's not simply letting them just have their way with him. To be fair, she sees Ichika as being her only family. She even has a 'woman-to-woman' talk about him with 5 of the girls. She later regrets this in the OVA when she talks to Yamada-sensei about it since she realizes that [[ThatCameOutWrong because of the way she said it]] -- she had a few beers during the talk as well -- the girls think she's [[BrotherSisterIncest yet another rival for her brother's affections]].

# It jeopardizes the friendship -- if the friend and the sister break up, the brother is put in a ''very'' awkward spot. The friendship should come first: BrosBeforeHoes.

# The brother is jealous of any guy who gets too close to his sister because they don't want to lose the position of #1 person in their sister's life. The IncestSubtext (if any) of this one varies due to factors such as the brother's age and exactly ''what'' they think being "#1" entails.

* Music/DieAntwoord's video for "Baby's On Fire," where the duo plays a pair of siblings, exposes the DoubleStandard this trope creates: Ninja sleeps with every girl in town, but flips out the moment Yo-Landi tries to have a sex life of her own, chasing every boyfriend away with increasingly-larger weapons. The video ends with her grabbing a brick and knocking him senseless as she runs off with her new love.

''[[https://archiveofourown.org/works/35091475/chapters/113577712 The Dragon's Son]]'': Kagami scares off anyone that tries to asks out [[CrossoverRealtive her cousin Izuku]], and says they would have to beat her in a duel if they want to date him. Justified as izuku ''is'' embarrassed that strangers are trying to date him and is too awkward to say no, so he's grateful that Kagami is turning them down on his behalf.

* ''LightNovel/MyNextLifeAsAVillainessAllRoutesLeadToDoom'':

* ''[[Fanfic/MyDeepestDarkestSecret My Deepest, Darkest Secret]]'': [[GenderInvertedTrope Well, brother, actually]]. It's mentioned that the vampires often scare off any admirers of Solon. Solon recalls a time seeing Jino, ''[[BewareTheNiceOnes of all people]]'', burn a bunch of love letters meant for him during Valentine's Day. Solon didn't even meet the wolves until the time of the story because a few years ago, they ''stared at him for a few seconds'' and they thought they were ogling him. Kind of {{justified}}, given that the people Solon tends to attract can either be a good or bad person, and the complicated nature of people makes it hard for them to tell which is which. [[spoiler: Luckily, aside from intense interrogating, Enzy didn't suffer when they found about his and Solon's [[OfficialCouple relationship]], and they even let them stay together]]. Interestingly enough, they were happy when it seemed like Solon got a love letter (really just a note from Enzy telling him to meet up somewhere) and Shion often teases him about having a boyfriend. Though since they were with the Nightball team at the time, it's likely they were just [[TheGadfly teasing]] him outside then planned on hunting the one who sent the letter later on, and Shion [[ShipperOnDeck actually seemed happy]] Solon was with someone who loves him.

* ''[[Fanfic/MyDeepestDarkestSecret My Deepest, Darkest Secret]]'': [[GenderInvertedTrope Well, brother, actually]]. It's mentioned that the vampires often scare off any admirers of Solon. Solon recalls a time seeing Jino, ''[[BewareTheNiceOnes of all people]]'', burn a bunch of love letters meant for him during Valentine's Day. Solon didn't even meet the wolves until the time of the story because a few years ago, they ''stared at him for a few seconds'' and they thought they were ogling him. Kind of {{justified}}, given that the people Solon tends to attract can either be a good or bad person, and the complicated nature of people makes it hard for them to tell which is which. [[spoiler: Luckily, aside from intense interrogating, Enzy didn't suffer when they found about his and Solon's [[OfficialCouple relationship]], and they even let them stay together]].
** Interestingly enough, they were happy when it seemed like Solon got a love letter (really just a note from Enzy telling him to meet up somewhere) and Shion often teases him about having a boyfriend. Though since they were with the Nightball team at the time, it's likely they were just [[TheGadfly teasing]] him outside then planned on hunting the one who sent the letter later on, and Shion [[ShipperOnDeck actually seemed happy]] Solon was with someone who loves him.

** Interestingly enough, they were happy when Solon got a love letter and Shion often teases him about having a boyfriend. Though since they were with the Nightball team, it's likely they were just [[TheGadfly teasing]] him.

* In ''Manga/RaveMaster'', Haru does this trope when he learns of the relationship between his sister Cattleya and [[spoiler:Shuda]]. He did this earlier when, another guy was dating Cattleya and broke up her heart. So naturally, when he saw said guy again, he made every effort to punch him out again. Not to mention [[spoiler:Shuda]] himself when finding out about that guy, he wanted to chop him up to pieces also.