[The following is a draft. Feel free to improve it by adding examples and otherwise fleshing it out.]

Large eyebrows are occasionally used to show that a character is old or wise, as they take a long time to grow out. Other times, they show that a character is powerful and stoic – their smallest emotions are magnified, and have more of an impact than they would with smaller brows. This latter use of eyebrows appears to be more common in anime and manga, while the former seems to be more prominent in western literature.

Examples of powerful mighty eyebrows include:

Magic eyebrows:

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Great flaming moe eyebrows at rest:

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You are witness to the legendary super great flaming moe eyebrows!

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Eyebrows with the will to save the world at any cost:

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When Kenshiro gets surprised, he's basically lifting weights. He lives in a very surprising world. This has made him so strong he's essentially invincible.

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Eyebrows of power:

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Yup, here too…

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Koichi! Remember, those are lethal weapons!

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Eyebrows are often symbolic. Sometimes, they're just a part of a person's face.

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Reduced eyebrows can mean that a character's emotions are fruitless, no matter how strong the character is physically.

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