Ema Hinata's father has decided to remarry a woman named Miwa Asahina. When she goes to move into the Sunrise Apartments, she meets her new brothers: All 13 of them!

Brothers Conflict began as a series of novels, divided into two cours: the first one is set when Ema is in high school, while the second has Ema entering into university. It has been adapted into two otome games by Otomate: ''Brothers Conflict: Passion Pink'' and ''Brothers Conflict: Brilliant Blue'', the latter to be released in 2013. An anime by Creator/BrainsBase started airing as part of the [[Summer2013Anime Summer 2013 Season]].

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* AcademicAthlete: Subaru attends the Meiji University and is in the basketball team; because he dedicated his whole life to absolutly nothing but sports, he has no clue about how to deal with Ema, having no experiences with women at all.
* ArrangedMarriage: Masaomi was going through this in the books. However, he politely declined the arrangement. Why? [[CrowningMomentOfHeartwarming Because he promised Ema that he would be by her side.]]
* [[spoiler: AttemptedRape: In episode 10 of the anime, Fuuto was about to rape a sleeping Ema, because in his words, "You [Ema] belong to me." Thankfully,he doesn't go threw with it, because he realizes that he truly loves her.]]
* BabiesEverAfter: [[spoiler:Masaomi's ending.]]
* BeautyMark: Natsume has one on the chin, the twins have one next to one of their eyes.
* {{Bishonen}}: Ema's stepsiblings are all pretty boys.
** CastFullOfPrettyBoys
* CharacterDevelopment: Because of Ema's influence, all of the Asahina brothers have changed or matured dramatically than what they were in the beginning.
* DevelopmentHell: The two games were delayed several times. The second one, ''Brilliant Blue'', has yet to be released; and ''Passion Pink'' had several bugs after finally being released.
* DisappearedDad: What happened to the Asahina brother's birth father?
* DoItYourselfThemeTune: The anime ending is sung by the boys and Juliis seiyuus.
* [[spoiler:DumpThemAll: All she ever wanted was to have a family, and towards the end of the first season she finally made it clear. How effective that act was, however, is another question altogether.]]
* EverybodyIsSingle
* FlirtyStepSiblings
* FreudianTrio: The triplets: Natusme is the Superego, Azusa is the Ego, and Tsubaki is the Id.
* HappilyMarried: Rintaoru Hinata and Miwa Asahina.
** [[spoiler: Ema's birth parents: Kenji and Yukie Nagami.]]
** [[spoiler: Masaomi and Ema in Masaomi's ending.]]
* HeroicBSOD: [[spoiler:Ema has one upon learning that she's adopted.]]
* HouseHusband: Ukyo acts as the mother figure to the family.
* HugeGuyTinyGirl: Ema is this with one of the taller, muscular brothers in a different route: Kaname, Subaru, Natsume, and Ukyo.
* IdolSinger: Fuuto is this, and he's also quite popular.
* {{Jerkass}}: Ukyo's ex-girlfriend, Reiko Amamiya, only dates him to get closer to his mother and didn't care about him at all.
* LookalikeLovers: {{Inverted}}. In Ukyo's route, Ema (new love interest) looks like his ex-girlfriend, Reiko.
* MakingLoveInAllTheWrongPlaces: [[spoiler: In Kaname's route, it's heavily implied that he and Ema had sex in his car at night.]]
* MassiveNumberedSiblings
* MayDecemberRomance: In the games, if the player decides to pair Ema with any of the older brothers.
* TheNicknamer: Juli and Rui call Ema "Chii".
* NotBloodSiblings: The whole point. [[spoiler:Doubly so once Ema finds out that she's adopted.]]
* NunTooHoly: Kaname is not a very good Buddhist monk.
* PeekABangs: The identical twins Azusa and Tsubaki have specular bangs covering one of their eyes.
* RapunzelHair: Hikaru, and [[spoiler: Yukie Nagami (Ema's birth mother).]]
* SecondLove: [[spoiler: Ema is this in Iori's route.]]
* {{Seiyuu}}: Two of the three triplets, Azusa and Tsubaki, in-universe.
* SiblingRivalry: Yusuke vs Fuuto and Tsubaki vs Azusa. To be honest, except for the otome game, where the player can choose one of the brother's route, the Asahina brothers are all "love" rivals for Ema.
* SpeaksFluentAnimal: Ema talks with Juli, her pet squirrel, all the time. Later we find out that [[spoiler:Rui, or "Luis", is also able to do that]].
* TheirFirstTime: Ema has her "first" with a few of the brothers in a different route. The following includes: [[spoiler: Tsubaki, Kaname, Masaomi, Hikaru.]]
* TokenMiniMoe: Wataru, of course.
* WhatCouldHaveBeen: The otome game is basically this: What would have happened if Ema had chosen fallen in love with one of the Asahina brothers?
* WholesomeCrossdresser: Hikaru, his crossdress was so good to make Ema fall for it, the heroine initially thought that he was a real "she".
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