On My Level 50 char with 30 Vit: Headless Bloodletting Beast
Key is using the iframes from quicksteps as much as possible.
Rune: + 20% stamina, +15% HP, +4 vials
Get your weapon of choice, saw spear short form for me, and mash R1 the whole time, keep enough stamina to quickstep twice.
I do the left leg technique, but i stay locked on as much as possible. There is only a couple of move you have to predict. Its important when you end up under him, mostly, because when you go behind or beside him he cannot do much.
Watch for the 2 hands smash, good wind up before it so its easy to see it coming. When he raises his arms, quickstep to your right to end up beside him. When he raises one arm to start a flurry of fists to the ground, quickstep a few times to get behind making use of iframes as much as possible.
Taking damage is part of the fight, do not run to heal, heal under or beside him and get back to R1 attacks or dodging as fast as possible.
There is pretty much only those 2 attacks you have to worry about the whole fight if you stay close to his left leg or under him. You will likely die a few times to a succession of combos or getting stunlocked from his movement in between 2 combos preventing you from healing. No worries, he will fall eventually, take a deep breath, stay focused looking for those attacks and it will be fine. Its a good 40% luck, 30% reading his moves and 30% saving damage from dodging and iframes imo.
Good luck fellow hunters!!!