Genkai's role on her series is kind of wasted, as talented a fighter as she is. She could've been a soul reaper like Yoruichi was. I just love watching both women fight. Neither would rely heavily on the use of a sword, but rather their own powers and brute strength. The rules to this fight are don't hold back, give the battle what you got, and have fun with it. Of course no whining is allowed, like Yoruichi ever does that. And to start this fight, Genkai went to her younger version, just to make things fair.