There is always a female version of a male character, no exceptions.
In other words, every male persona or character from a video game, commic, manga, anime, etc. has been feminized by someone, somewhere on the internet. Such feminizations are usually in the form of an image macro or fanart.
Rule 75 is an axiom summarizing behavior & content that one may find on the internet, which has its origins from 4chan (a large image board). Similar to rule 34 and other "internet rules".
That rule 75 for akuma is hot! (Note: Akuma is a male video game character from the Street Fighter series of fighting games)