This doggy maybe fast and hurtful, but his patterns are predictable and easy to dodge. However, his attacks CANNOT be blocked. I tried multiple times and just waited patiently for him to attack while guarding. You can only succesfully dodge or get damaged with this guy. Also, he'll only spam 2 attacks the entire fight, then a low HP arte later. The issue is these 2 spam abiilities do a decent amount of damage which is annoying. Best method is to pound away at him. If your the main target, watch which head he uses, then dodge to the opposite side of that head. Then if he still attacking you, HE ALWAYS does the same attack (different element) the other way. Same plan. One way of defeating him is to make him target you, then just dodge his attacks. Set your friends to "all out" in attack so they won't be hit.