Head in at least level 20 but honestly its more about knowing his moves than your actual level. You'll want plenty of stamina so dump most of your sparks in that part of the foundation tree and make sure you've got enough health since he hits like a truck. Maybe interesting: his Roar And Smash move always starts with him getting down on all fours, and that Quick Slash has this really obvious stance you can spot from far away. Good to know that upgrading your dodge skills and counterflow abilities makes a huge difference, and having Guangmou as your spirit summon helps a ton during his aggressive phases.

The stone form decoy part trips up a lot of people but if you save your Immobilization spell for when hes winding up big attacks, you can lock him down and get some good hits in. Something helpful to keep in mind is that its worth spending some time just learning his patterns without trying to win, cause once you know how to dodge his basic stuff, youll be ready no matter what level you are. Cloud Step works great for avoiding his attacks, especially during that stone phase, and remember its totally fine if you need a few tries to get it down since hes pretty tough. The main thing is just practicing those dodges and learning when to counter instead of worrying too much about hitting a specific level first.