The Brief: Rule number 63 of the internet states that "for every fictional character, there exists an opposite-gender counterpart."

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The formal definition for Rule 63 is

For every given male character, there is a female version of that character.
For every given female character, there is a male version of that character.

Such character recreations are often posted to DeviantArt. Some people cosplay as gender swapped or genderfluid versions of characters from books, movies, anime, and other fandoms.

Although this rule assumes a gender binary, many characters are transformed through fan art and fiction to defy traditional gender norms. These include genderqueer and nonbinary reimaginings of fictional characters.