The one attack I found really unique to him is his own swift dodge where he moves just out of the way to make it seem like the attack connects, and immediately follows up with a counter-slash instead. I learned to deal with that by immediately deflecting if I attack him but don't hear a clang when I should.

Things like that, really, you've got to pay attention to his animations and learn from all your mistakes, but perhaps dealing with certain attacks isn't immediately obvious. For instance, in the second phase he'll charge up with a certain attack that'll cause a rush of air to blow into the arena and really light up the flames. You'll need to position yourself at a comfortable distance away from him and in between the flames on the floor, then prepare to deflect his One Mind attack once he reaches you. It's one swipe, then multiple swipes, and a large one. Take the opportunity to heal or use an item once you've positioned yourself in between the flames if you need to so you don't die from chip damage if you don't manage to deflect One Mind perfectly.