Sort of like the Hair Contrast Duo, this trope sees a (seemingly always male) partnership consisting of a blond warrior/soldier or general action guy type, and a dark-haired Brainy Brunette or magic user. This foil focuses less on the personalities of the duo than on their niche as characters. Either one could be arrogant, shy, stubborn, good, bad, etc. But their hair color inevitably matches what they're "good at."

Examples:

• Sherlock and John, from Sherlock
• Merlin and Arthur, from Merlin
• Tony Stark and Steve Rogers from The Avengers
• Thor and Loki, from The Avengers - sort of. They're not really...friends.

• I probably need a TV trope for the warrior/soldier/action guy thing, if anyone can think of one, and the magic user
• Probably needs more content. This is just a quick draft
• Needs more examples...

(be gentle, its my first time)