Red Oni, Blue Oni/Professional Wrestling

Professional Wrestling is chock-full of these. To wit:
 * The Brothers of Destruction: The Undertaker (Blue) and Kane (Red).
 * In Kane's second most notable tag team, with The Big Show, Kane plays the Blue Oni to Show's Red. Kane tends to be the more stoic (if psychotic) of the two, while Show ranges anywhere between Hot-Blooded to Big Fun.
 * The Hardy Brothers: Jeff Hardy (impulsive and aerial Red) and Matt Hardy (more calculated and ground-based Blue).
 * Edge (blue) and Christian (red)
 * Former WWE Unified Tag Team Champions Mike "The Miz" Mizanin (angry Red) and John Morrison (mellow Blue).
 * The Rockers (originally AWA's Expies of the Rock 'n' Roll Express from the NWA), Marty Janetty (Blue) and Shawn Michaels (Red); notable for the fact that the group originally split after they gradually switched roles over the course of their 5-year tag team career.
 * In the same vein, the current iteration of D Generation X, with Shawn Michaels back in the Red Oni role and partner/best friend Triple H in the Blue Oni role (it can also be noted that Hunter can switch the colors pretty much on demand now as a story needs him to).
 * Classic big-man tag team The Twin Towers, where the Big Boss Man (prior to his Heel Face Turn) was the Red Oni and Akeem "The African Dream" (after switching gimmicks from the One Man Gang) was the Blue Oni.
 * The Outsiders, Kevin Nash (Blue) and Scott Hall (firmly entrenched in Red terrritory).
 * Even Mick Foley (jokey Red) and Al Snow (serious Blue) meet this trope head-on!
 * The Rock and Sock Connection: Foley remains the jokey Red while The Rock is the serious blue.
 * Even the ANNOUNCERS get in on the action!
 * The classic team of Jim Ross (Blue) and Jerry Lawler (Red).
 * Classic ECW's Joey Styles (Red) and Joel Gertner (Blue). OH MY GOD!!
 * Michael Cole (Red) and Tazz (Blue).
 * When Tazz went to the ECW Brand, Cole became the Blue to John Bradshaw Layfield's hard-Red.
 * Gorilla Monsoon (Blue) and Jesse Ventura (Red). Gorilla was firmly Red, however, when teamed with Bobby "The Brain" Heenan (cold, calculating Blue).
 * On that token, "Rowdy" Roddy Piper lived up to his moniker when he served as Monsoon's replacement Red with Brain.
 * In TNA, you have Mr Anderson (rule-breaking, stubborn asshole Red) and Matt Morgan (higher-minded, honourable Blue), although, in an ironic twist, Anderson's entrance lighting is very blue-themed whereas Morgan's is very red.
 * Raw and Smackdown are this right down to their colors.