History RedOniBlueOni / AnimeAndManga

* There are numerous cases that could be argued from ''{{Bleach}}'': Ichigo and Ishida, Ichigo and Byakuya, Renji and Byakuya, Ishida and Renji, Grimmjow and Ulquiorra, Kenpachi and Byakuya.
** In Episode 35 of the anime there are two cases when charaters are shown as such. First Aizen (Red) and Ichimaru (Blue) in a flashback. Then Hitsugaya (Blue) and Ichimaru (Red).
** Ginjou and Tsukishima. No colour association so far, but we'll see what the anime guys come up with.

* In ''LuckyStar'', we have [[{{Tsundere}} Kagami]] [[DeadpanSnarker Hiiragi]] (Red) and [[TheDitz Tsukasa]] [[CloudCuckooLander Hiiragi]] (Blue). With Konata's cousins, we have [[AdultChild Yui]] [[DrivesLikeCrazy Narumi]] (Red) and [[IllGirl Yutaka]] [[TheIngenue Kobayakawa]] (Blue).

* Keroberos and Yue of ''CardCaptorSakura'' fame also qualify; [[TheStoic Blue Oni]] Yue is often cold, introspective, and seemingly totally dispassionate, while [[TheIdiotFromOsaka Red Oni]] Kero-chan is hot-headed and emotional.

** For the Marines, Admiral Akainu (Red), who is prone to passionate bouts of well-intentioned extremism, and Admiral Aokiji (Blue), who is very laid back. [[{{Lampshading}} Even their names reflect this-- "aka" is red, "ao" is blue]].

* On the same side, but Ryoma and Hayato from ''GetterRobo'' definitely fit. Ryoma's a heroic burning-sense-of-justice type([[AxCrazy well,]] [[HeroicSociopath most]] [[BerserkMode of the time...]]), while Hayato is a cold-blooded loner. This is taken into extremes in ''Getter Robo G'', where Ryoma's Getter Dragon is red and Hayato's Getter Liger is blue!

** Just 02? Let's see, in the first ''[[DigimonAdventure Adventure]]'', we have the main character, Taichi, who Daisuke is an {{Expy}} for, and so they share a lot of personality traits (albeit Taichi's are toned down a little), and AloofBigBrother [[TheLancer Lancer]] Yamato, who spends most of his time [[BigBrotherComplex trying to figure out what will keep his younger brother safest]]. While Taichi is unrestrained emotionally, Yamato is more prideful and tends to get embarrassed quickly at activities that lower him down to Taichi's level. Taichi is associated with the color orange (at least it's close to red), and Yamato with the color blue.

* ''SkyGirls'' has Ranko and Haruko Mikogami, as shown in the picture above, who fit this trope to a T.

* Jin and Mugen from ''SamuraiChamploo'' are perhaps '''the''' epitome of the trope. They are not only dressed in the respective colors and are [[{{Foil}} foils]], they represent every trait possible of the trope. Water and fire ([[AnimalMotifs fish and rooster]] in the OP), past and future, tradition and innovation (TechnicianVersusPerformer), orthodox and unorthodox, predictable and unpredictable, economy and extravagance, controlled purpose and chaotic energy, [[OrderVersusChaos order and chaos]], [[EmotionsVsStoicism stoicism and emotion]], etc. Jin is practically unable to feel passionate about anything or form attachments to anyone, while Mugen is reckless passion without direction or purpose (or the brain power to put it to use). Fortunately, [[CharacterDevelopment they get better]] throughout all the whirls of yin and yang.

* Jin and Mugen from ''SamuraiChamploo'' are perhaps '''the''' most triumphant example. They are not only dressed in the respective colors and are [[{{Foil}} foils]], they represent every trait possible of the trope. Water and fire ([[AnimalMotifs fish and rooster]] in the OP), past and future, tradition and innovation (TechnicianVersusPerformer), orthodox and unorthodox, predictable and unpredictable, economy and extravagance, controlled purpose and chaotic energy, [[OrderVersusChaos order and chaos]], [[EmotionsVsStoicism stoicism and emotion]], etc. Jin is practically unable to feel passionate about anything or form attachments to anyone, while Mugen is reckless passion without direction or purpose (or the brain power to put it to use). Fortunately, [[CharacterDevelopment they get better]] throughout all the whirls of yin and yang.

* Ame-warashi and Zashiki-warashi, the fairies of ''{{xxxHolic}}''. Ame-warashi has red hair and is brash, rude, and aggressive, while the blue-haired Zashiki-warashi is the shy, quiet, kind one.

* ''YuYuHakusho'' has ''literal'' blue and red oni -- the blue oni are the bureaucrats in the Spirit World, while the red oni are security. With the protagonists, Yusuke and Kuwabara are both brash and eager, ready to throw themselves at a challenge, while demonic protagonists Hiei and Kurama are far more calculating and keep much cooler heads about them.

* In ''{{Prince of Tennis}}'', Kaoru Kaidoh (skittish, kinda naïve, aloof) and Takeshi Momoshiro (cheerful, a bottomless pit, carefree) might not dress in red and blue, but otherwise they fit the trope to a T. And yes, they play doubles.

* ''OnePiece'' has two giants, Dory and Brogy, respectively titled "The Red Ogre" and "The Blue Ogre" on their wanted posters, although they both act [[HotBlooded the same to this troper]]

* Light and L from the ''DeathNote'' anime series are often shaded in red or blue to reflect this, although personality-wise it doesn't ''quite'' apply, since aside from a few times that Light gets riled up after his cause is challenged, ([[spoiler:and just before his death]]) both Light and L tend towards being brainy, cold blooded types. This theme is also used (and generally played much straighter) with Misa and Light, Light and Near, Mello and Near, and even Misa and Takada.

* Tomoe and Nanami ''Manga/KamisamaKiss.'' Nanami is red; passionate, energetic, frequently acts on impulse, very extroverted. Tomoe is blue; is very proud along with being much more calm, intellectual, tends to think before acting and is more introverted.

* ''AzumangaDaioh'''s Red Oni homeroom and English teacher Yukari, who is goofy, carefree, fun-loving, and irrational, and wears bright red and yellow clothes, contrasting Blue Oni P.E. teacher Nyamo, who is cautious, caring, responsible, thoughtful, and wears darker blue clothes. Red Oni Tomo and Blue Oni Yomi also fit the trope.

* In ''{{Mai-HiME}}'', Mai Tokiha is the Red Oni (emotional, passionate, concerned with people), and Natsuki Kuga is the Blue Oni (aloof, mysterious, and concerned with goals). They even have hair colors to match (Mai's is [[RedHeadedHero reddish-orange]], and Natsuki's is [[YouGottaHaveBlueHair bluish-violet]]).
** Mirrored by Arika (red) and Nina (blue) in ''{{Mai-Otome}}''. In the prequel mini-series, Nina's mother Sifr plays Red to Arika's mother Lena's Blue, seemingly just for the irony.

*** [[TheHero Ed]] is a HotBlooded {{Hair Trigger Temper}}ed InsufferableGenius in a red BadassLongcoat. [[TheAragorn Roy]] is a laid-back {{Magnificent Bastard}} (heavy emphasis on {{The Chessmaster}}) in a blue BadassLongcoat. Coincidence? [[spoiler:I think NOT!]]

* Michio Yuki and Father Garai from ''{{Manga/MW}}''.

* In ''AxisPowersHetalia'', Red Oni America is cheerful, idealistic, brash, if a little too much; whereas Blue Oni England is his cynical, grouchy, critical, sometimes underhanded, longtime '[[FriendlyEnemy frenemy]]'.

* [[CainAndAbel Rin and Yukio]] from ''AoNoExorcist''. They may be [[HalfIdenticalTwins twins]] but they're completely different: Yukio is a prodigy exorcist-doctor while Rin is the HotBlooded [[AntiAntiChrist son of Satan]].

* [[LotteNoOmocha Not only do Lotte and Asuha]] wear the matching colors for their roles (well, Asuha wears pink, but close enough), but Lotte is of course a demon (oni) [[spoiler: and Asuha is half, meaning this borders on VisualPun]].

* Goku and Vegeta of ''DragonballZ'' exemplify this trope to a point where it could be named for them.

* Kirche and Tabitha from ''ZeroNoTsukaima''.

* Ayano and Kazuma from ''[[{{KazeNoStigma}} Kaze no Stigma]]''. Ayano has a fiery, impulsive, very caring personality, while Kazuma has a calm, impassioned, jaded personality. The colors fit them too; in the OP, Ayano is colored red, Kazuma blue. Kazuma has blue eyes when his power is activated, and a general blue theme, and Ayano has red hair and reddish eyes.

* ''{{Pokemon}}'': The American release of the first two games, Red and Blue, sort of mirrors the trope. Also, from the anime, we have Ash, the {{Idiot Hero}}, as the perfect example of the Red Oni, while Gary, TheRival, definitely qualifies as the Blue Oni. Paul, Ash's new [[TheRival rival]], seems to have taken over the Blue Oni role, mixed with {{Jerkass}}. To a lesser degree, Zoey and Nando also qualify.
** ''Pokémon Adventures'' features the heroic trainer Red and his rival, Oak's nephew Blue. In the Japanese original, ''PokemonSpecial'', however, this was not the case, as Red's rival was Green, while Blue was the female trainer that the English-language version called Green.

** ''{{Pokemon}}'' manga love this trope. [[PokemonDiamondAndPearlAdventure Hareta and Mitsumi]], [[PokemonGoldenBoys Gold and Black]], [[PhantomThiefPokemonSeven Hiori and Lily]]..