Red Oni, Blue Oni/Real Life/Sports

Examples of in  include:


 * Shaquille O'neal (red oni) and Tim Duncan (Blue oni)
 * Karl Malone was the blue (blue-collar work-ethic, more reserved demeanor) to Charles Barkley's red oni (party animal, loud, very outspoken).
 * Choleric tennis star John McEnroe had a famous rivalry with the imperturbable Bjorn Borg.
 * Ohio State (FUCK! THE! WOLVERINES!) and University of Michigan (alumnus Mike Wallace: "They say [Michigan] is intellectual and snobby. And I guess that's true.").
 * USC and UCLA. The Trojans in cardinal and gold tend to be more proud and arrogant as the red onis, while the Bruins in True Blue and gold tend to be more intellectual and nerdy.
 * City rivals Rice (blue) and Houston (red) fit this trope to a T, in both their student body profiles AND their respective choices of school colors.
 * The University of Georgia and Georgia Tech. The colors even match, as Bulldogs (in red and black) are rough and rowdy sports fans while the Yellow Jackets (in white, gold, and navy) had a reputation for being intellectual "engine-nerds."
 * Boston Red Sox (blue collar, ironically) and New York Yankees (metropolitan)
 * Like Dr. Manhattan, everyone is a hot-blooded underdog compared to the New York Yankees.
 * Anaheim Angels and Los Angeles Dodgers (just for color, they both used to be blue)
 * The Washington Capitals and Pittsburgh Penguins, embodied by the playing styles and personalities of their respective superstars: the Caps' Alex Ovechkin (red) and the Pens' Sidney Crosby (blue). Appropriately, Washington's primary color IS red, while Pittsburgh used blue as its primary color until 1980 and recently brought it back for their alternate jersey.
 * Eternally present in European Football Clubs, especially as most local rivals tend to wear Red and Blue to contrast each other intentionally.
 * In Italy's Serie A, AC Milan wears red, and they're a passionate club, with a fanbase mostly from the lower class. Inter wears blue and their policy is calculating, with their devoted fans coming from the upper class.
 * Merseyside's Liverpool FC and Everton FC play in red and blue respectively. Liverpool's supporters also have the incredibly passionate theme song You'll Never Walk Alone.
 * Manchester United and Manchester City. United is the much more fiery one, given their huge fanbase (accounting to 5% of the world's population) and the number of silverware they accumulated over the years. City is much more closer to the upper class Mancunians and residents of the city proper, in contrast to United's wider demographic.
 * Arsenal and Tottenham Hotspur, also known as the North London Derby. Arsenal is Red, with a very diverse multiethnic fanbase. Tottenham is Blue and is supported by the conservative Jewish population of London.
 * A teammate example: Italy's and AC Milan's midfield duo, the fiery, aggressive Gennaro Gattuso and the cool, efficient Andrea Pirlo.
 * Another teammate example: Chicago Blackhawks stars Jonathan Toews and Patrick Kane. Together the two are the face of the team and, to an extent, the NHL as a whole. Kane tends to be a bit more excitable both on and off the ice while Toews exhibits a much more cool and collected personality.
 * The three major Texas colleges fit a slightly mutated version of this trope. The University of Texas is the high profile, upper class, some would say snobbish blue oni. Texas Tech is the hot blooded, unsophisticated, very red Scrappy. And Texas A&M is kind of the purple middle man, who can fill either role depending on which of the other two they're facing next..
 * Dallas Cowboys (blue and silver) and Washington Redskins (burgundy and gold). Coincidentally, the Redskins are currently one of the only two teams who has an official marching band and one of the few to have their own fight song (Hail to the Redskins).
 * NFL team the Pittsburgh Steelers have a pair of outside linebackers who sort of fit. LaMarr Woodley is the Red Oni and James Harrison is the Blue Oni. LaMarr is more talkative, more likely to celebrate (every sack he records is followed by the most awkward flying side kick ever witnessed), and generally more energetic. James is a quiet, not-quite-right-in-the-head fellow with a penchant for perpetrating unspeakable violence with little noticeable emotion.
 * The Calgary Flames and Edmonton Oilers of the late '80s were an inversion. The blue-coloured Oilers were young and high-scoring, led by the likes of Wayne Gretzky, Mark Messier, and Jarri Kurri, while the red-coloured Flames played more of a defensive, tight-checking game.
 * The University of Arizona and Arizona State University are both red-ish in both school colors (Arizona's is cardinal red and ASU's is maroon) and reputation (both are party schools) but Arizona is considered to be a better academic institution and also has navy blue as its other school color, while ASU's second is gold.