Western adaptation Kamen Rider Dragon Knight also qualifies, though Kit Taylor (Dragon Knight) isn't as Hot Blooded or impulsive as most Red Oni; he really only looks a little that way when compared to Len (Wing Knight).
Kamen Rider Blade has Blade as the Red Oni (and The Hero) and Garren as the Blue Oni (and The Lancer). Played with in that their main colors are the opposite of their personality (Blade, the Red Oni, is mostly blue in color, while Garren, the Blue Oni, is mostly red.)
Kamen Rider Kabuto has Kagami Arata and Tendou Souji, who fit the trope to some extent, but with some notable exceptions:
The blue oni, Tendou, is the main hero.
Any victories that Kagami achieves are won at length and through actual effort, not handed to him for free by virtue of Dumb Is Good.
The colours of their suits are reversed: Kabuto (Tendou) is red and Gatack (Kagami) is blue.
Kamen Rider Den-O has Momotaros, the red oni looking one, who loves the thrill of a good fight. Then there's Urataros, the blue one, who keeps cool at all times and prefers to use deception to get out of sticky situations and score with the chicks.
Kamen Rider Decade has Tsukasa/Decade and Daiki/DiEnd, although Tsukasa is normally more blue in personality...until Daiki shows up. Their suits mostly match their roles, although Decade is magenta, not red.
Kamen Rider W gives an interesting triangle. While Philip almost-always plays Blue Oni to both Shoutaro and Terui (if Philip is playing Red Oni, then you know it's a bad situation), Shoutaro's "hard-boiled yet passionate" and Terui's "cold and distant yet volatile" personalities regularly has them switching roles, depending on who's Red at the moment.
W's only red/blue combination is HeatTrigger, which inverts Philip's and Shoutaro's colors.
Accel's suit starts out red, but his power-up of Trial Mode is blue. This actually mirrors Terui calming down as the series progresses.
Although Justin and Alex, from Wizards of Waverly Place, are both sarcastic and, to an extent, Deadpan Snarkers, they have really different personalities. While Alex is witty, prankish, and lazy, never taking anything seriously (represented by red), her older brother, Justin, is responsible, much more mature, studious, and collected (represented by blue).
The interesting thing is that in their wizard competition, they reversed the associated elemental roles, with Justin showing more of an affinity for fire, while Alex tended to use water.
Many Super Sentai and Power Rangers series have the Red Ranger as a Red Oni, and several have the Blue Ranger as something of a Blue Oni. Few have their relationship as a major theme, though.
Tokusou Sentai Dekaranger has Ban Akaza, the Red Ranger/Oni who is chaotic but friendly, and Hoji Tomasu, the Blue Ranger/Oni who is professional but arrogant. The American version, Power Rangers SPD, does the same with Jack Landors and Sky Tate, although Jack does not embody Dumb Is Good to the same extent as Ban.
Choushinsei Flashman reverses colors with its duo: Jin, the Red Flash, is the more sensible and mellow Blue Oni, whereas Dai, the Green Flash, is the strong, arrogant, and frightening Red Oni.
Mighty Morphin' Power Rangers fit the trope to an extent - the Red Ranger was the confident, extremely physical leader of the band while the Blue Ranger was the intellectual brainiac of the bunch. The other three members (the Pink/Girl, Yellow/Asian, and Black/Afro-American Rangers) probably fall under Unfortunate Implications...
Of course Kyoryu Sentai Zyuranger is rather different from its American remake - Tyrannoranger Geki is calm and smart by default, as Triceraranger Dan is dumb, brash, and wanting to rush into a fight.
Whenever the Power Rangers writers get lazy and make the Rangers expies of Sentai, the theme shows up more. Often Sentai will have the Hot Blooded Red who lives by Dont Think Feel and the calm expert Blue. Power Rangers tones down the loud screaminess of the Reds but falls back on Rookie Red Ranger to the point that the dynamic is the same: a Red who's winging it and an expert Blue, who's actually more likely to be annoyed with Red than in Sentai. It's worse when the Rookie Red is given formal authority. (See, it's known that Red is "always" the leader, but half the time, "Leader" seems to mean "Red stands in the center for the Super Sentai Stance because it's habit." Nobody ever actually said Leo or Mack were in charge of anything; but in SPD and Wild Force, that's not the case, and the guy who doesn't know what he's doing outranking the one who does is a way to keep the friction going for quite some time.)
Jack O'Neill and Dr Daniel Jackson from Stargate SG-1 could fit into this trope as many of the earlier episodes' conflict came from O'Neill's emotional pragmatism conflicting with Daniel's intellectual desire to study and understand various things. Interestingly, this is often reversed in later seasons - Jack descends into rational, Black-Ops mindset as Daniel plays up his I-empathize-with-everyone side.
Ronon and Teal'c have this kind of relationship in the Stargate Atlantis episode "Midway". Ronon being the aggressive and wild Red Oni and Teal'c being the calm and cultured Blue Oni. And both being The Big Guy of their respective show.
Rodney McKay is Red Oni to almost any other scientist that appears on the show, notably Zelenka, Beckett, and Beckett's replacement and McKay's love interest, Dr. Keller.
Unusual in that Rodney is usually smarter than his Blue Oni, which makes up for his often-times unscientific professionalism. When he plays opposite Samantha Carter, who is the only scientist in the SGC that he accepts as being better than him, McKay plays a bit more traditional Red Oni.
On Judge Judy, a calm woman with dyed-blue hair sued an angry woman with dyed-red hair.
Firefly loves playing with this trope and stretching the boundaries of it as far as they can go, sometimes with mind-bending results.
Mal and Simon are set up at the start to look like Red Oni and Blue Oni; Simon's even set up to look like a villainous Blue Oni. Then the truth is revealed and from that point on, it's very clear that while they superficially look like an ideal Red Oni, Blue Oni example, they're actually a case of Not So Different, as Simon is every bit as passionate and willing to break the rules and law as Mal. As it turns out, he's even got a better talent for crime than Mal - at least, when it involves a subject he's familiar with.
Jayne and Simon have an equally interesting dynamic. Their Red Oni, Blue Oni relationship is deliberately used to play them against each other in almost every scene they share. However, who is Red and Blue actually changes depending on the situation. For all of Jayne's hot-headed, uncultured nature, he's also a very level-headed Combat Pragmatist with sometimes surprisingly accurate assessments of people and situations. This is often used to compare and contrast with Simon's cultured intellectualism that only superficially masks his deeper passion and idealism.
In a similar sense to Simon and Jayne, Jayne's pragmatism is sometimes used to play villainous Blue Oni against Mal's heroic Red, especially with regards to the issue of keeping Simon and River on the boat. No-one can deny the sheer logic of Jayne's attitude, but Mal's far too compassionate to be swayed by it.
And yet at the same time, Jayne's immediate recourse to violence, his impulsive nature with money or loyalty, and his immediate, snap dislike of Simon (contributing to his attempt to get him off the boat ) makes him a pretty good candidate for Red. They play the roles very well, but the Red/Blue divide mostly seems to depend either on the issue at hand, or which characters eyes you're seeing it through.
Mal's most obvious Blue Oni counterpart is Zoe, who is also a Blue Oni to her husband's Red Oni.
There's also one going between Simon (Blue Oni) and Kaylee (Red Oni).
To an extent, this also applies to Mal and Shepherd Book. Although Book has a somewhat rough, earthy nature akin to a red oni, he is also a very intellectual, spiritual, and cultured individual. Besides that, there's his heavily hinted past with the Alliance, which is about as blue an organization as you can find.
This trope fits very well with LOST. Jack - though a doctor, which is very blue in nature - is a very passionate, people-oriented, and frequently rebellious leader. Locke, on the other hand, is more preoccupied with spiritual matters, such as destiny and purpose, as well as more learned in a greater variety of fields. Interestingly enough, though Locke has also frequently shown signs of the blue oni villain through his coldness towards others, Jack's ruthlessness is far more potent, as depicted when Locke cannot bring himself to shoot Jack in order to stop him from talking to the freighter people, but Jack is fully willing to shoot Locke when the two next encounter each other.
Though, when it comes to classic Evil Blue Oni, it's pretty hard to match Ben.
And Sawyer is both in one person!
Peter and Nathan Petrelli from Heroes. Nathan takes the role of the Aloof Big Brother while Peter is the younger, emotional, and, unfortunately for many, an Idiot Hero. Also, Peter and Sylar, according to how their powers work (Peter's is empathy, Sylar's is intuitive aptitude). However, in Season 3, Peter absorbs Sylar's ability, making him have the hunger, and Sylar has had Peter's ability all along. Also deconstructed in a future episode, where Peter summons fire while Sylar summons ice. It makes even more sense since Peter and Sylar are revealed to be brothers.
Except it's later revealed that was just a lie and they are, in fact, not brothers.
Also, if you compare the heroes with their future selves, who are all apparently Badass. It's inverted in the case of Sylar, where he moved into Claire's home, calls himself Gabriel (his real name) and is much nicer than his present self. He even has a son named Noah.
Inverted in the case of the siblings Meredith and Flint. Meredith has the red fire, but she is much calmer and more level-headed than her younger brother, who's about as bright as a flea but has the blue fire. However, since Meredith is on the side of good, she possesses a genuinely warm (pardon the joke) and caring personality for her family while her brother is ruthless and even killed a woman with his powers.
Also, in an early first-season episode, Mohinder and Sylar are speaking about Mohinder's father (who was actually murdered by Sylar, unknown to Mohinder). At first, both are lit by a blue-green light, but when the murder comes up, Sylar turns away from Mohinder and smirks, and his face is lit in a red light. Mohinder's still in the blue light.
This dynamic plays out with several characters in The Wire:
Jimmy McNulty and Bunk Moreland possess this dynamic: McNulty's a free-wheeling Cowboy Cop who yells, cusses, gives a fuck when it ain't his turn to give a fuck, and generally plays by his own rules, whereas Bunk is quiet, direct, and by the book.
Avon Barksdale and Stringer Bell possess this as well. Avon's the shrewd but hotheaded leader of the Barksdale organization, while Stringer generally seeks to avoid conflict and instead see the practical side of things, and attempts several times to make legitimate business pursuits.
Homeless heroin addict Bubbles is the Blue Oni to his more impulsive friend Johnny Weeks and later to naive protege Sherrod. Both Red Onis die due to their incautious nature while Bubbles escapes the street.
Felicia "Snoop" Pearson and Chris Partlow, the enforcers for up-and-coming drug dealer Marlo Stanfield in Season Three, also form this dynamic. However, the one time Chris truly loses it, even Snoop is amazed.
Jed Bartlet (red) and Leo McGarry (blue) from The West Wing fit this trope to a tee — in fact, a good portion of Leo's job is to act as Bartlet's cool-headed, hard-nosed, deep-thinking Blue Oni counterpart, pulling the passionate, sensitive, deeply moral, and idealistic President back from the brink with logical arguments when he gets too angry, vengeful, excited, righteous, irrational, or quixotic.
Spock (fittingly costumed in blue) is a classic blue oni on Star Trek: The Original Series; on the occasions when they're not all chumming it up as a Power Trio, Kirk and McCoy each often serve as the red oni to his blue, depending on who's playing off whom at the moment. Red and blue aren't specifically used as contrasting colors for them—McCoy wears blue as well—but their red human blood and his "cooler"-colored green Vulcan blood are often contrasted.
According to Shatner's autobiography, one problem they had with the original pilot, The Cage, is that Captain Pike and Mr. Spock were too similar. If you were going to have an unemotional Mr. Spock, then the captain needed to be very emotional so that they could play off of each other, and that's how Shatner played him. Also, the show originally was meant to be Kirk and Spock, and the Kirk/Spock/McCoy trio developed on its own. (Note that only Shatner and Nimoy have "I get what he gets" clauses in their contracts.)
That doesn't make sense, because in "The Cage", Spock wasn't unemotional at all. It was Pike's first officer, Number One, who was logical and calm, cool, and collected.
Also, the show buys into this trope in a more general way: science and medical personnel, the knowledge-oriented "brains", wear blue, while operations; security and engineering, the action-oriented "brawn," wear red.
In Star Trek: Deep Space Nine, we have the rival temporal beings the Prophets (very cold in their interactions, theme color blue, basically "good" if kind of confusing about it) and the Pah-Wraiths (subtle about nothing, spewing red flames all over the place, unmistakably evil).
In a more general sense, the Federation (blue) and the Klingons (red) fit this pretty well in the 24th century, including the color scheme (for instance, the graphics used for their transporters and their emblems).
Despite that Worf is a blue Klingon and Jadzia is a Red Starfleet officer.
Jadzia is the blue oni in her friendship with Kira - Jadzia often being more level-headed and relaxed, while Kira is...Kira .
In any episode featuring the Mirror Universe, the mirror characters are quire literally the Red oni to the main series' Blue. However, only in Star Trek: Deep Space Nine do characters actually meet their mirrors in person.
Prison Break's protagonists, brothers Lincoln Burrows (red) and Michael Scofield (blue), fit this trope to a T.
While not on the same shows (or even the same channel), "dueling" chefs Buddy (Cake Boss) and Duff (Ace of Cakes) have opposite personalities: Buddy is extremely Hot Blooded while Duff is considerably more relaxed; this extends to their surroundings: Buddy's bakery is a neighborhood institution and is mostly staffed with his family (including his four older sisters) while Duff only does specialty cakes and is surrounded by his friends.
The promos for both of these shows does the same. The promos for Cake Boss are usually with a warm reddish background, with the famous red TLC logo. In contrast, most of the promos for Ace of Cakes are done in shades of blue and even color the Food Network logo blue.
Blake's 7 has two pairs of these, one on each side, for the first two seasons: red oni Roj Blake, passionate freedom fighter, frequently reckless, and his Lancer, blue oni Kerr Avon, coldblooded "what's in it for me?" tech, versus blue oni Servalan, primary power of the evil Republic, and her revenge-obsessed red oni, General Travis.
In season 3, with Blake vanished, Avon ends up stuck with red oni/brash youth Tarrant while fugitive Servalan doesn't bother to replace the dead Travis.
A Disney Channel movie called "Stepsister from the Planet Weird" had this for the two families: the down-to-earth Earthlings were blue while the literally air-headed (they're bubbles) and overly emotional aliens were pink/orange. Naturally, their wedding theme was purple.
The Casablancas brothers on Veronica Mars. Dick is stupid, impulsive, never thinks things through, loud, and sex-obsessed. Beaver is intelligent, quiet, reserved, manipulative, secretive, and completely ruthless.
Also, Logan and Duncan. Duncan (blue) is reserved and somewhat emotionally restricted, whereas Logan (red) is pretty much the dictionary definition of Hot Blooded.
And, in flashbacks, Lilly and Veronica. Lilly was the brash, wild one (red), whereas Veronica was sweet and demure (blue) before (things changed).
"The Persuaders!", an English crime series, has two main characters: the aristocratic Brett Sinclair (Blue), who is cultured, clever, charming, and has a dry British humor, and Danny Wilde, a self-made American rich (red), who is hotheaded, uncultured, and very enthusiastic.
Buffy the Vampire Slayer and Angel both have this with the vampires Spike and Angel. The former being Red, the latter being blue. Especially in Season Five of Angel.
Also, Buffy and Kendra. Then Faith and Buffy. And maybe Willow and Tara in season six.
When Willow and Tara first meet in Season 4, Tara wears blue and Willow wears red — Tara is shy, cautious yet with longer experience in magic use, while Willow is more powerful, impulsive and (by that stage) outgoing in personality.
A nice example in Homicide: Life on the Street with the duo Bayliss/Pembleton. Bayliss is a somewhat Emo young man who is tragically unable to keep emotionally distant from his job and is given to outbursts of violence, but is also caring and sensitive. Pembleton is an older, smarter, educated, cold, and occasionally smug professional.
At the end of the pilot of Leverage, you see a group shot in which the two most hot-headed and aggressive of the crew (Nate and Eliot) have on red ties, and the two most calm and collected members of the team (Sophie and Hardison) are wearing blue. Of course, Parker, being the resident sociopath, has no color scheme.
Dean and Sam from Supernatural are red and blue, respectively, especially during the first season.
Except, as Character Development marches on, they switch places: Sam is revealed to be much more hotheaded and reckless, and Dean revealed to be more of a stoic. It's most obvious when you compare their reactions to each other dying. Dean cries perfect, single Manly Tears and asks Sam what he's supposed to do now. Both times Sam is faced with Dean's death (in "Mystery Spot" and during the four months before Dean was resurrected), he cries first but soon after sets about avenging him.
Saturday Night Live gave us loud, cocky Wayne Campbell (red) and shy, nerdy Garth Algar (blue).
In Unnatural History, there's the adventurous, bold Henry Griffin (red) and his level headed, stick to the status quo cousin Jasper (blue).
On 24, Jack Bauer and Tony Almeida play these roles to each other - with Jack as the Rabid Cop red oni and Tony as the (relatively) controlled, business-like blue oni.
Keen Eddie: Eddie Arlette (red) and Monty Pippin (blue).
The Mighty Boosh: Many characters pair off and start redding and bluing it up, especially anyone in a conversation with Naboo, the show's resident Blue Oni. Howard and Vince often play with the red and blue chemistry, but they're more like a couple of purples putting up a front.
Fiona and Michael have been this since the very start in Burn Notice. Now that Jessie has been added to the team, (who is both a male Red Oni and also a spy like Michael) it brings up all sorts of interesting chemistry, not to mention the vastly different approaches that Jessie and Michael bring to their job.
The main stars of MythBusters, Adam Savage and Jamie Hyneman. Both do the same job, but Adam does it flying by the seat of his pants, laughing and exclaiming over every explosion or test result, while Jamie coolly looks on. When one myth required them to use a remote control airplane to test the myth, co-star Grant talked about the differences in personality.
Grant: Adam is a very exuberant personality, so I expect him to crash the plane very quickly. Jamie is a much more controlled personality, so I suspect he's going to be able to fly it better and that he'll be our pilot in this test.
As you can tell from that quote, Grant himself is blue. His counterparts in the Build Team, Kari and Tory, are both red.
Merlin and Arthur with the quieter, more sensitive Merlin usually in darker, earthier colors while Arthur usually wears brighter, flashier clothing. Somewhat justified as Arthur is a prince and would wear fancier clothing.
It should be noted that while Merlin may be quieter and more sensitive than Arthur, he fulfills plenty of the red oni qualifications on his own.
Teen Wolf: Scott and Stiles fit this trope to a T, with Scott as the Red Oni and Stiles as the Blue Oni. Scott is more impulsive, passionate and reckless; these traits were magnified after he became a werewolf. Stiles is the Blue Oni; he is more logical, calm and composed and doesn't get as emotional and hot headed as Scott.
The Vampire Diaries has a rather unusual example with the brothers Stefan and Damon, with the younger brother Stefan playing a heroic Blue to his older brother's Red. Damon is impulsive and passionate and tends to flip between anti-hero and villain on a whim, while Stefan is usually measured and controlled.
In the early seasons of Farscape, D'argo and Zhaan have this relationship, down to the colors. It's played with, though, as both also have Hidden Depths. D'argo, at heart, wanted nothing more than a simple farm life with his family, while Zhaan's cool exterior hides a seething rage that is terrifying to witness when it breaks through.
John Crichton and Scorpius can also fall under this heading, particularly when they're forced to team up: Crichton is outgoing, exuberant, and (especially in the later seasons) more than just a bit crazy, while Scorpius is cold, calculating, manipulative, and ruthless. Once again, both have hidden depths: for all his eccentricities, Crichton is still a scientist, and by the end of the series, he's developed a knack for planning ahead and adjusting said plans at speed; Scorpius, on the other hand, hides a vicious temper under his reserved exterior.
Blue Bloods: Henry and Danny are red onis; Frank, Erin, and Jamie are blue onis.
Delenn is a Blue Oni. Londo is bluer than G'kar but less blue than Delenn. G'kar is red. Sheridan is very blue.
Ivanova is an uptight and militaristic officer who is usually blue but she often seems to have a bit of redness buried deep inside. Marcus Cole might go either way but his devotion to an order of Warrior Monks is more blueish. Garibaldi has more than a bit of redness, surprisingly for a security officer. Franklin is definitely blue.
The Shadows are red and the Vorlons are blue. Minbari are blue, humans and centauri are in between, and Narns are red.
In Battlestar Galactica, Apollo is blue and Starbuck is red. Boomer can be the blue to Starbuck's red as well.
Same would go for Starbuck's lovers, the hot-tempered Athena (red) and the more tolerating Cassiopeia (blue).
The spiritual Adama (blue) and the cynical Tigh (red) could arguably fit the bill as well.
In Starsky and Hutch, the street-smart Starsky (red) and the book-smart Hutch (blue).
Dexter: Dexter himself is blue and each of the main killers of each season are red.
Also, his sister Deb might qualify as red.
In BBC's Sherlock, Sherlock Holmes is the intelligent, aloof Blue Oni to John Watson's more emotional Red Oni.
Torchwood currently has emotional, impulsive Gwen Cooper and cool, almost perpetually blasÚ Captain Jack Harkness. In past seasons, hotheaded, profane Owen Harper and reserved, polite Ianto Jones played Red and Blue respectively when interacting with pretty much anyone else.
Frasier (red) and his younger brother Niles (blue). Note that this does not mean Niles is any less neurotic or eccentric than Frasier, just that he has a far milder temper. Their demeanors fit the mold (Frasier's brand of conceited pompousness is overbearing and Hot Blooded while Niles' is fussy and sharp-tongued) and Niles is more down-to-earth by comparison whenever Frasier gets caught up in his ridiculously over-emotional trains of thought, irrational schemes and obsessions, and explosions of anger or vengeance.
The Nanny: Fran Fine (appropriately called "The Lady in Red" in the theme song) and Maxwell Sheffield.
Psych: Impulsive, intuitive Shawn (red) and thoughtful, cautious Gus (blue).
Breaking Bad plays around with this. For starters, Jesse Pinkman and Walt White epitomize recklessness (youth) vs. calculation (experience). Hank and Walt similarly reflect this, mainly with the former's direct, almost obnoxious way of dealing with his family and job. However, Jesse plays Blue when dealing with his less smart cohorts Badger and Skinny Pete. Walt and Gus Fring also flip this around: the first acts more out of emotion and concern for his family and (sometimes) Jesse. The latter, who has no emotional attachments the audience knows of (or at least living ones), conducts business the way only a cold-blooded monster would, taking extreme caution to keep his respectable businessman facade while not minding his underlings' (or anyone else's) deaths to keep his drug distribution outfit operating.
On Gilmore Girls, there's the pro/con list making Rory and the frustrated Paris.
Americas Next Top Model, full stop. At least one model per cycle borders on absolute Red; at least one other borders on absolute Blue; and everyone else falls in between, depending on whom they're compared to.
Their father Dan is the Jerkass red while their Cool Uncle Keith is the obvious blue.
The red and blue universes from Fringe. The people from the red universe are Darker and Edgier compared to their counterparts from the blue universe, who are the main characters of the series.
Ultraman Gaia has Takayama Gamu (Gaia, red Ultraman) an idealist who believes that the Gaia's purpose is to save Earth and humanity. And Fujimiya Hiroya (Agul, blue Ultraman), who is more focus on defeating monsters and more interested in protecting just the planet itself, even at the expense of humanity. Fujimiya eventually Tooka Level In Kindness, but remains as more cool head.
In Modern Family, it's astoundingly able to pull off a Red Oni, Blue Oni dynamic with pretty much any pair-up between the three main families. Within the parents there are Claire and Phil, Gloria and Jay, and Cameron and Mitchell. With the kids, Haley and Alex along with Luke and Manny. The pairs and even roles get switched around constantly.
The Inspector Lynley Mysteries: Barbara Havers is red, Thomas Lynley is blue. However, as is this show's habit, the reality is slightly more complex: Havers is certainly more fiery and hotheaded in daily life, but she is generally the cool, collected one in a crisis, whereas Lynley is usually the more rational and pragmatic one, but tends to panic when the shit hits the fan. Also, Lynley is more likely to fly off the handle at suspects, whereas Havers is more likely to react with Tranquil Fury.
"Austin & Ally", impulsive Austin (red), and level-headed Ally (blue).