On the series official site, Benimaru Nikaido has been said to be loosely based off a comic book character and that to this day, the staff still call him by the character's name. A developer interview first seen in the "All About KOF '94" mook eventually confirmed that the character is based off Jean Pierre Polnareff from the third arc of the long-running manga series "Jojo's Bizarre Adventure":

Benimaru Nikaido Benimaru was modelled after Jean Pierre Polnareff from JoJo’s Bizarre Adventure... as such, for a long while the developers called him by that name instead of Benimaru. His design went through a lot of changes and experimentation too. For example, at one point he wore a tank top t-shirt. Also, in his win pose he says “san kyuu!” (thank you) in that funny voice. When Benimaru’s designer first heard that voice, it was so far from his original image of the character that he got enraged and couldn’t do any work for the rest of the day. Which leads us to a question we often get asked: is Benimaru gay? My answer is, he’s a man’s man. He loves women, if I had to say. Maybe he’s a little narcissistic as well?
Contributed by Mutsukki