Was doing this content on Veteran, and while I did have a problem with my second arena fight for the summoners, nothing else got anywhere near knocking me down. what was hilarious, however, was when the grand champion ended up positioning herself with her back to one of the spike traps. I was playing a Breton Templar with a greatsword and that attack with knockback. She was at about 3/4 health when I hit her with that attack, and she fell into the trap, dropping her down to a hair's breadth of health, which didn't last long. I don't think there was ever a more perfect setup for winning a fight.