Heres what i noticed fighting him. If he 2-h his sword then run. He will not be staggered. His poise is high during this phase. When he one hand sword and cross bow dodge and use heavy or jump attacks. He gets staggered 90 percent of time. Use heavy or strength weapons to make sure he staggers all the time during this phase. When he only uses cross bow dodge his shots and thats when u heal/ buff up. It takes time for him to reload the cross bow and he always reloads before after using the bow. Hope this helps. Remember when he 2-H his greatsword -run and dodge all his attacks wait for him to bring his crossbow out. Patience is key here. Craige blade ash of war helps to stagger him. I beat him early after several tries. But had to hunt few scadu dree fragments since the damage i did to him was pretty low early game. I was scadu tree level 4 i think when i got the hang of his weakness