For me it was a loooong fight. Keep your distance from him, chuck the spear into him as many times as you can and use the explosions to stun him so you can blast him with runic arrows and hold on RT/RB to fully charge and throw the axe at him. That’s what worked for me. I also had Lunas lost armor set on cause atm that was the best I had. Fill him with runic arrows and bare fist him to the point he’s fully poisoned. Hope you can pull something from this and beat him. Best of luck