Kyo from King of Fighters can defeat every boss as if it's nothing.
Though he lost to Goenitz once because he was fighting alone.
Maybe that's because he's a protagonist? From what i heard, SNK almost never lets their protagonists lose.

No offense to them, even though i like KOF, a protagonist winning every battle is poor/bad writing in my opinion and maybe even considered plot armor. If they lose at least once or twice, it makes me happy because i know they are not undefeatable people who can defeat everyone without trying.

Sorry if i am off-topic by the way.