Screw this, Dust though, I'm not dying for sciences sake.  A moment before the creature was on him he side stepped and moved around her, with the agility, skill, and timing that a swordsman acquired only from many years of experience and many fights.  He brought his sword across a fast and powerful blow that slammed into the back of her head and made a muffled clang when it bounced. He settled in a guard position a meter or so away.  The next time it came at him he would go for a wing maybe, or something else.  He wouldn't be getting through it's hide,  as he had just seen, even if he could only cut the softer parts of her body though he could still use his sword as a very effect cudgel if nothing else.