This is my boss fight, I'm sharing some of the tips I found in order to avoid more damage. This is not a guide; a guide should be exhaustive in details and consider several playing styles.
More details about my build in case you want to know.
Lvl. 167
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Vigor 35
Attunement 10
Endurance 40
Vitality 42
Strength 37
Dexterity 53
Intelligence 15
Faith 14
Luck 10
Stamina 176
Equip load 86.9
Poise 35.87
Refined Bastard Sword+9
Grass Crest Shield
Morne's Helm
Black Knight Armor
Black Iron Gauntlets
Black Iron Leggings
Chloranthy Ring+1
Flame Stoneplate Ring
Ring of Favor+1