It's the aesthetic more than the characters being established elsewhere first. tbh, the latter hardly matters at least to me.
[rant]
I find it sad that "anime fighter" nowadays makes me sigh and think of Koihime Enbu waifus, Rachel Alucard, Vatista, Heart Aino and that abominable puddle grappler loli from AH3. It makes me think of May and Jam destroying my hearing and sanity.
It could be making me think of aesthetics like Samurai Showdown, TTGL, Moribito, Juuni Kokki. It could conjure up images of Sol fighting Faust or Ky or Zato. It could make me imagine this:
https://www.youtube.com/watch?v=SBA6PItBqvo
It could, in short, be
good. But good doesn't sell body pillows. And I'll get Bridgets and Rachels to the day I die or something.
[/rant]
RIP KOF.