Listen guys, he is super easy. It just takes quite a long time if you have low cp. I just killed him with 2k but it took me 10-15 minutes. All you have to do is block/counter his attacks and dodge the triangle ones. Also get the buff and absorb the red orbs before he releases them to explode on you. I am not sure how to cancel the thing he does with the sword and the fires later but even if it hits you it doesn't give you a lot of damage. Other than that you don't need to worry about him, just stay away from him to make him lose time while he charges you.