Crossover
- Aura of the Azure (BlazBlue & RWBY): Ragna (Red) tends to be aggressive and rash, while Jin (Blue) is cold and calculating. Word of God even gives an example as to how they would operate as police officers combating corruption in a law enforcement organization. Jin would work tirelessly to locate the source of the corruption and ensure that the law punishes them without mercy. Ragna, meanwhile, would just brutalize and terrorize any corrupt cop he encounters.
- Arctic Rim (Frozen (2013) & Pacific Rim): Elsa is more analytical and cautious in her fighting style (Blue), while Anna is more instinctive (Red). They pass greater or less amounts of control to each other depending on the situation; Elsa handles more of the longer ranged weapons, outfighting, and ground-grappling, while Anna handles the Kinetic Strike Module and clinch fighting.
- Child of the Storm (Harry Potter & Marvel Cinematic Universe)
- Harry and Carol alternate between the two roles. On the one hand, Harry's the one with emotional repression issues, Nerves of Steel, a habit of very dry snarking, and when he gets really angry, the result is Tranquil Fury. Carol, meanwhile, is a loud, Hot-Blooded teenager with anger issues and a bit of impetuosity. On the other hand, Harry's also increasingly got a Hair-Trigger Temper which he struggles to keep in check, is practically the poster boy for the Indy Ploy and Didn't Think This Through and his signature power is Playing with Fire. Meanwhile, Carol is reserved, cautious about trusting people, Harry's self-appointed Morality Chain who never loses control of herself, functions as The Strategist for Harry and his friends, and has an increasingly disciplined mind, sufficient to earn the right to wield the Green Lantern Ring.
- Steve is the Red Oni to Bucky's Blue Oni, with the former being more emotional and explicitly more connected to his humanity, while the latter is/used to be the Winter Soldier, and retains a cold, ruthless and intensely pragmatic streak, as well as tending to be quiet, thoughtful and patient, while Steve - though not lacking caution or pragmatism himself, will always stride straight into battle as soon as required.
- Thor and Loki, of course. Thor's the Red Oni, Loki's the Blue Oni.
- Jean Grey and Maddie Pryor/Rachel Grey. Jean is sweet, lovely, an absolute sweetheart who's open with her emotions... and possessed of a spectacular and terrifying temper. Maddie/Rachel, by contrast, is almost entirely calm, practical, logical, reserved, and capable of being very, very cold - though post Heel–Face Turn, the facade cracks somewhat.
- Children of Time (Doctor Who & Sherlock Holmes): Has Beth's red to Holmes's blue.
- Cinders and Ashes: the Chronicles of Kamen Rider Dante (Kamen Rider & Re:CREATORS) plays with this trope. The Volcano and Avalanche Belts are specifically made to use the powers of emotions as a power source when they can't draw from their respective elements, with the Volcano Belt using passionate or angry emotions and the Avalance Belt using more cold-blooded emotions. However, this gets flipped around, as the holder of the Avalanche Belt uses it for his Roaring Rampage of Revenge while the holder of the Volcano Belt has cooled down his emotions.
- A Triangle in the Stars (Gravity Falls & Steven Universe): While Steven is undoubtedly the Red Oni to mostly everyone else, he's the Blue Oni to Bill Cipher's Red. Later, however, Bill evolves into more of a Blue Oni, and Steven himself bounces back and forth from Red to Blue.
- While usually the Blue Oni in the show, Connie is actually the Red to Wendy's Blue. Though they very rarely switch roles.
- Stanley Pines is the Red to Stanford Pines's Blue, and Peridot is the Blue, and sometimes Red, to both of them.
- Garnet is the Blue to Pearl's and Amethyst's Red, and Pearl is the Blue to Amethyst's Red. When Keyhole joins, he becomes the Blue to Pearl's Red.
- Gabriel is and has always been the Red to Bill Cipher's Blue.
- And finally, Jasper is the Red to Lapis's Blue. It helps that they're actually a version of red and of blue respectively.
- In Eight Count, the calm and confident veteran boxing champion Kate Kane is the blue to the wild and undisciplined red of rookie boxer Harley Quinn.
- In the fanfic Disgaea: Jewel of the Gods
, Laharl is the red oni to Adell and Mao's blue oni. Adell and Mao tend to trade role for who's the red oni and who's the blue oni of the two.
- Vow of Nudity: Spectra assumes this dynamic with the princess she's sent to rescue from the faewilds. The princess is headstrong, impulsive, aggressive, and risk-taking, whereas Spectra is nervous, submissive, self-doubtful and overly accommodating to the various hostile parties they encounter on their trip home.
- The fanfics That's What Being Friends Is About and The Pride Of Twoson depict Ness as being shy and introverted (Blue), in contrast to Paula's bold, confident demeanor (Red).
- Children of an Elder God (Cthulhu Mythos & Neon Genesis Evangelion): Asuka is the Red Oni -being fiery, high-spirited and loud- and Rei the Blue Oni -she is quieter, colder and usually emotionless-. As a bonus, Asuka has fire-related powers.
Game of Thrones / A Song of Ice and Fire
- Our Blades Are Sharp: Roose Bolton's sons Domeric (blue) and Ramsay (red). Domeric is calm, pragmatic, and kind-hearted, while Ramsay is impulsive, hedonistic and sadistic. This is reflected in their clothing; Domeric mostly wears blue or black with hints of red, while Ramsay is shown wearing predominantly red and no traces of cooler colors.
Godzilla / King Kong / MonsterVerse
- Abraxas (Hrodvitnon):
- Zig-Zagged with Mothra. As lampshaded by the narrative, Mothra is normally "the serene mirror surface of a still sea" to Godzilla's "unpredictable and tumultuous sea in a storm", but Mothra herself can become just as ferocious as the King of the Monsters when she's pissed off enough.
- Madison Russell is the Blue Oni to her father Mark's Red Oni, being collected and introverted during the story, and being a voice of reason to her Hot-Blooded father when his emotions get the better of him. Madison even has a dislike of humidity in contrast to her father's aversion to cold climates.
- Natural Selection: Ryuko and Junketsu are the red and blue oni respectively. While both share an equal amount of blood-lust and sadism, Ryuko is far more hot-headed, reckless, and impulsive while Junketsu is more logical, calm, and inquisitive.
- In The Story of Apollo, Daphne and Luca: An Italian Tragedy, there are many examples:
- Alberto and Luca. Alberto is outspoken, boisterous and confrontational, while Luca is mild-mannered, soft-spoken and adverse to conflict. It doubles as Opposites Attract since they gradually start a Puppy Love romance.
- Carlos and Bianca, with Carlos being the Red Oni (an outgoing, cheeky Gossipy Hen) and Bianca the Blue Oni (a level-headed, aloof Deadpan Snarker).
- Giulia and Luca are also a platonic example like Carlos and Bianca, with Giulia being a fiery, adventurous Tomboy who is never afraid to speak her mind and Luca a calm and gentle Shrinking Violet.
- Kitsune no Ken: Fist of the Fox gives us Suigetsu and Jugo, red and blue respectively. Suigetsu is Hot-Blooded, while Jugo's more calm and methodical.
- In White Rain, it is Sasuke who is the Red Oni to Naruto's Blue, strangely enough. Their relationships also have the same distinction.
- Advice and Trust: Asuka and Rei. The differences between them become less extreme after Rei stops taking emotion-suppressor meds, but Asuka is still hot-blooded and impetuous and Rei is still quiet and calm. During the story their friendship develops and they become a very close-knit combat unit together with Shinji.
- A Crown of Stars: Avalon's army commanders Ching and Bir. Ching is the Red Oni -enthusiastic, mirthful and passionate- and he is the Blue Oni -calm, serious and somewhat staid-. They are also a Battle Couple.
- In Ghosts of Evangelion Asuka is the Red to Shinji's Blue. She is hot-blooded, quick-tempered and impetuous, and Shinji is calm, rational and passive. She helps him be more assertive and he keeps her calm.
- HERZ: Asuka is the red oni (she is temperamental, rash and hot-headed) and Rei the blue one (she is calm and soft-spoken). Due to their clashing personalities there was some hostility between them when they were young, but after twelve years it has mostly faded.
- Higher Learning: Asuka and Shinji were this for a long time. They were always together, and Asuka was the hot-headed, enthusiastic Red Oni and Shinji the quiet, meek Blue Oni. This changed after Asuka's Mind Rape, and she became silent and gloomy.
- Last Child of Krypton: Passionate and fiery Asuka is the Red Oni while collected and silent Rei is the Blue Oni. It was specially noticeable in scenes where Asuka reacted and acted while Rei prefered waiting and analyzing the situation.
- The One I Love Is...: Asuka -Hot-Blooded, hot-headed, angry, loud- and Rei -emotionless, detached, calm, quiet-. Their relationship greatly evolves throughout the story. At the beginning Asuka detests Rei and Rei ignores Asuka. Later, when they start competing over Shinji, they can not stand each other. Finally, after a violent fight, they make up, call a truce, and they gradually become friends.
- Rise of the Minisukas: Shinji is guarded by the leaders of the Minisukas, Leader and Shiki. Leader (Red Oni) is an emotional, loud show-off. Shiki (Blue Oni) is morose and quiet.
- In The Second Try, Asuka is the Red Oni to Shinji's Blue. Although she's calmer and he's less timid due to their increased maturity, she's still daring, bold and passionate whereas he tries to be a calming, pacifying influence.
- Superwomen of Eva 2: Lone Heir of Krypton:
- Asuka was the Red Oni -passionate and temperamental- and Shinji the Blue Oni -meek and quiet-. Actually, Asuka liked Shinji -among other reasons- because he knew how to listen.
- When Asuka and Rei hang together and fight together, Rei -quiet and passive- is the Blue Oni.
- Pokémpanions has Plusle and Minun, Plusle is red colored and energetic and reckless, and Minun is calm and cautious and is blue colored.
- Pokémon Reset Bloodlines shows it often:
- Ash is the red to Paul's blue. Ash is exuberant, warm, and thinks on his feet; whereas Paul is subdued, cold, and prefers to plan ahead.
- Gary and Red also have this sort of dynamic. Ironically, Red's the Blue Oni, being quiet and stoic; while Gary is the loud, emotional Red Oni.
- Ash and Red also have this dynamic, with Ash as the red and Red as the blue. This is reflected in their respective abilities. Ash has the ability to temporarily increase his Pokémon's power, while Red is able to see "victory odds".
- Seth in the Pokécity: While both share the Only Sane Man role, Tim Tim is a short-tempered, impulsive Fiery Redhead, especially when Flosshead is involved (Red) while Seth is mostly laid-back, rational and sarcastic (Blue).
- Traveler: In contrast to the source material, Ash is blue to Gary's red. He serves a similar role to his early travelling companion Jonathan. Lance and Steven's relationship has tones of this, with Lance as red and Steven as blue.
- The Return-Remixed has DEAR's Big Bad Duumvirate, Trish Stratus (Red) and Lita (Blue). Trish is cocky and arrogant when things are going her way, but loud and hot-headed whenever they're not, while Lita is more level-headed and rational.
- Peace Forged in Fire plays this contrast between Rahaen'Enriov D'trel ir'Aehallhah t'Rihannsu and Khre'Riov Morgaiah "Morgan" ir'Sheratan t'Thavrau, the two lead members of the Romulan Republic diplomatic team. D'trel doesn't like Velal, the Praetor of the Romulan Star Empire, and has diametrically opposed political views, and runs on Unstoppable Rage in battle, while Morgan is a more traditionalist Romulan, shares a friendly drink with Velal to hold the negotiations together, and has a much calmer, more rational fighting style. Also visible in their ship choices: D'trel's Kholhr is a Glass Cannon/Fragile Speedster T'varo-class light warbird, while Morgan captains a Mighty Glacier D'deridex-class battlecruiser.
- Blood and Honor: Vette - talkative, excitable, more at home in the underworld than anywhere else, wielding dual blasters and spending most of her free time in cantinas - versus Quinn - traditional, reserved, dedicated to the Empire and his duty, a consummate professional who looks down his nose at those he thinks are unprincipled or undisciplined.
- You Have To Help Me: Has this dynamic between Touka and her Muggle Best Friend turned One-Eyed Ghoul Yoriko. While Touka is obviously the Hot-Blooded one, Yoriko is cheerful and being careful. Ironically, their Kagunes show the opposite; Touka uses an Ukaku, while Yoriko uses a Rinkaku.
- Omoito: The short-tempered and abrasive Hourai serves as the red oni to the sweet-natured and gentle blue oni Shanghai. Fittingly, the covers of Eins and Zwei color Hourai and Shanghai red and blue, respectively.
- Better Bones AU:
- Stormcloud and Cherryfall, who are a romantic couple, form this sort of dynamic. Both love to fight but Stormcloud is calmer and Cherryfall is Hot-Blooded and reckless.
- There's also the calm and tactical Harestar contrasted with the angry and passionate Breezepelt, with both being two-thirds of the Harestar/Breezepelt/Heathertail childhood friendship turned polycule.
Unsorted
- The Child of Love: Asuka is the Red Oni and Rei the Blue Oni. Shinji compares them in the first chapter, saying Asuka is fierce and loud whereas Rei is calm and quiet.
- Doing It Right This Time: Asuka was the Red Oni -temperamental and impulsive- and Rei the Blue Oni -emotionless and quiet-. After returning to the past Asuka is calmer and Rei is learning to recognize and express her emotions, so differences between both are less extreme, but Asuka is still the passionate half of the duo and Rei the calm one.
- Dungeon Keeper Ami features Jadite and Ami, occasionally. Jadeite also fills the same role to Cathy. On the other hand, Tiger is a red oni to everyone, even Jadeite.
- Evangelion 303: Asuka is the Red Oni -she is hot-tempered, hot-headed, loud, boisterous, proud and impulsive-, and Shinji is the Blue Oni -calm, modest, quiet, patient, wary, understanding-. They are a Battle Couple.
- In the The Horsewomen Of Las Vegas, Becky Lynch is hands-down the Red Oni. She's brash, obnoxious, hot-headed and will kill without a second thought, but fiercely loyal to her people. She's such a Red Oni that it takes TWO Blue Onis to balance her out: 1) her working relationship with Charlotte Flair, who is an ice queen, diplomatic, The Chessmaster and very detached from others (Becky delights in driving her crazy) and 2) one of the Co-Dragons of her own merry band, Brooke Tessmacher, who handles most of Becky's business affairs because she's too impatient and impulsive to be able to do it herself.
- In Incorrect Smash Bros Quotes, the chipper, energetic Dharkon is the Red Oni, while the aloof, snarky Galeem is the Blue Oni...except when it comes to anger, in which case Galeem takes Red Oni to a whole other level.
- The Night Unfurls:
- Kyril's stoic, brooding nature means that he is the Blue Oni to many characters depending on the dynamic between any two. In terms of commanders, Drill Sergeant Nasty Bergen is the Red Oni. In terms of knights, his rival, Claudia (Alicia in the remastered version) is the Red Oni. In terms of his band of hunters, the choleric Sanakan and sanguine Lily are Red Onis. In terms of people who delved into the Eldritch Truth, Evil Sorcerer Shamuhaza is the Red Oni.
- Childhood partners in crime Sanakan (Red) and Hugh (Blue). While Sanakan is loud and tactless, Hugh is a mute who can only emote so much.
- Once More with Feeling:
- Asuka and Shinji are like this. Asuka is the Red Oni -temperamental, bold and daring- is the Shinji is the Blue -tranquil and quiet even when he is angry-.
- Rei -calm, soft-spoken- is also the Blue Oni to Asuka's Red one. Due to Shinji changing the timeline events they unexpectedly become friends, and better teammates (and Rei actually saves Asuka's from dying inside a volcano.
- Professor Layton and the Beam Katana Chronicles pairs the hot headed and rash Travis Touchdown with the calm gentleman, Hershel Layton.
- In the Great Chicken Miasma's Mario fanfic Better Off Alone, the young Yoshi Waffles is the Red to everyone else in the group's Blue.
- What About Witch Queen? has two pairs like this on opposite sides of war. On Arendelle side, general Kristiani is impulsive, "let's crush them now" red to Olafsen's more careful blue. On Weselton side, general Potter is red with More Dakka approach, while general Windsor is blue and described as "cold-blooded, sneaky bastard" by one of the Arendellans.
- Winter War gives us Ikkaku and Nanao, the co-leaders of the Hueco Mundo mission. Ikkaku is a Hot-Blooded Blood Knight with a newly acquired habit of giving nicknames and a physical fighter with no aptitude for kidou. Nanao is a serious, methodical, control obsessive Badass Bookworm and kidou specialist who so far has avoided hand-to-hand combat.
- Eris Game has Eri as the Red Oni and her best friend, Shiki, as the Blue Oni.
- The Palaververse: Second Sun: The titular second Celestia is a result of this situation, splitting into:Our impulsive self, containing all of our immediate aggressions and loves and fleeting fixations. And our higher conscience, devoted to higher matters of morality and the rules and plans we make for ourselves.
- Swing123 and garfieldodie's Calvinverse has Dr. Brainstorm as the red oni, with his foil Jack being the blue.
- The main cast also has this distinction. From most red to most blue, they are as follows: Socrates, Calvin, the MTM, Hobbes, Sherman, and Andy.
- To Kill A Thief has Light Yagami as red due to being crazy with Knight Templar ideas, while his partner, Miyako Toudaiji, is blue due to being sane with By-the-Book Cop tendencies.
- The Wizard in the Shadows has Harry as the Red Oni to Aragorn's blue.
- Apprentice has Sasuke and Mecha Sally.
- The dynamic between Chaos and Takato in the Tamers Forever Series is an interesting inversion of this trope. ChaosGallantmon has blue highlights on his armour, while Gallantmon has red highlights, and Chaos is also much more ruthless than Takato, but surprisingly enough, Takato is actually the Blue Oni, being much more subtle and thoughtful than the impulsive Chaos.
- Working Together has Rika Nonaka as the Red Oni and Arch-Enemy Valmont as the Blue Oni.
- Vale Whitaker, the Shrinking Violet heroine of the Hunger Games fanfiction Some Semblance of Meaning, is the Blue Oni in contrast to several Red Oni in the story, including her sister Maybelle, her district partner Kit, and Fiery Redhead Fen.
- The Medaka Box fanfic World as Myth has the friendship between the violent Unzen and the phlegmatic Choujabaru.
- A Necromancer's Wild Card has Ayumu Aikawa as the Red Oni to Minato Arisato's blue.
- The Snow Has Stopped The Rain has Zangetsu, who's crude, violent and hot-blooded (red) and Shirayuki who is (usually) calm, collected and proper (blue).
- Wonderful (Mazinja) has Taylor, who is the Red to Emma’s Blue. The former is bold and loud whereas the latter is calm and rational. Emma often helps to keep Taylor grounded.
- In Thousand Shinji:
- Asuka is the red oni and Rei the blue one. Reinforced because Asuka's powers are fueled by fury and fierceness, and Rei's by joy and despair.
- Shinji is also the blue to Asuka's red. She is a furious, passionate physical fighter. He is a calm, conniving schemer.
- The crossover Crossfire has Vash and Brandon as the Red and the Blue respectively. Vash is a loud, cheerful donut-loving goofball who always tries to resolve every conflict peacefully. His favorite flower is red geranium, and when he somehow gets in a fight, he will always find a way out with various tricks. On the other hand, Brandon is a cool and quiet undead mobster who won't hesitate to injure or even kill people when it's necessary to resolve a conflict. His favorite flower is forget-me-not, and whenever he gets in a fight, he tends to bulldoze everything in his path with brute strength.
- In Cardcaptor Rad, there's eager and passionate Hot Shot whose something of a Blood Knight, and calm, meticulous Red Alert, who'd rather wait and plan things out. Unsurprisingly they clash a lot.
- In Just a Child, Kanna's twin brothers Kim-un and Yushkep act in this fashion, with Yushkep as the red and Kim-un as the blue.
- Duos like this are widespread in the Teen Titans Our Own League novels, but the most prominent is Gar and Raven. The only ten year-olds in a school for teen heroes, they spend a lot of time together and are close friends (possibly more) despite the contrasts: Gar wears warm colors with white, Raven wears cool colors with black. Gar is hyperactive, mischievous and impulsive, Raven is quiet, pensive and Wise Beyond Her Years. Gar has a flashy power he cannot yet control, Raven's sorcery is understated because of how much control she has. In a reversal, Gar is a Sad Clown who hides his pain, while Raven always says exactly how she feels.
- In Hellsister Trilogy, the lead character Kara is a passionate, hotblooded hero (Red), and her partner Dev-Em is a pragmatic, analytical secret spy (Blue).
- Qwex67s Ultraman Z has the Crosswire sisters, Darlie and Darlene, who are the red and blue Oni respectively.
- Ships Ahoy!: Oprah is the Red Oni, being Hot-Blooded and headstrong, while O'Donahue is the Blue Oni, being more calm, collected, and levelheaded.
- Jiang Wei and Xiahou Ba in Farce of the Three Kingdoms. Jiang Wei is a Blood Knight, and Xiahou Ba deals with his boss's psychotic tendencies by means of calm resignation, to the point where he tells the death scene judges "I'm good," when prompted for last words.
