Huh... just beat the BSB without using any health items after dying against it way too many times. Apparently attacking a bit then running away(as in most of the length of the area away) doesn't work well. This time I just dodged toward him and hit him 2 or 3 times from behind while he was in the attack animation and then he dodged away from me... well, like the rest of the game, that changes up pretty much everything that most games teach you.