I started working on this catalyst last week. Got to the level 7 boss, hit him a few times and got the 20%. This week however I can't seem to get it. I've faced the level 7 boss 5 times, 3 of those times I was exclusively hitting it with the special attack. The current boss is the tanky knight so it's not a case of the Ogre boss with the weak spot, I was getting damage numbers every time but despite this I cannot seem to get the 20%. I tried hitting his head for crits (yes, swords do crit), I tried aerial and ground based attacks but nothing worked. I'm stumped, any advice?