Elden Ring PC | How to cheese Black Blade Kindred boss fight in Bestial Sanctum solo on NG

I just repeatedly use Night Maiden's Mist near the entryway that he can't get past and I try and keep him there. You can crouch behind the nearby pillar to avoid his attacks. Be sure to allocate enough flasks to Cerulean Tears. The more patient you are, the less Crimson Tears flasks you'll need.

Drops:
88,000 runes
Gargoyle's Blackblade
Gargoyle's Black Halberd

Black Blade Kindred
"Black Blade Kindred is a Boss in Elden Ring. These large stone gargoyles are held together with black corpse wax, indicating their allegiance to Maliketh. This is an optional boss, as players don't need to defeat it in order to advance in Elden Ring. However, doing so yields useful Items and Runes."
https://eldenring.wiki.fextralife.com/Black+Blade+Kindred

Bestial Sanctum
"Bestial Sanctum is a Location in Elden Ring found in Dragonbarrow. You can arrive at this location by exploring the northeastern portion of Dragonbarrow through Caelid or by using a teleporter in Limgrave, near the Third Church of Marika, after talking to D, Hunter of the Dead and obtaining directions."
https://eldenring.wiki.fextralife.com/Bestial+Sanctum

Night Maiden's Mist
"Night Maiden's Mist is a Sorcery in Elden Ring. The Night Maiden's Mist spell creates a dense mist before the caster, which deals damage to everything within it."
https://eldenring.wiki.fextralife.com/Night+Maiden's+Mist