Cheesing Black Blade Kindred because I was over it

I fought Black Blade Kindred awhile back when I was low level and finally came back after being level 100 -- but it still wasn't enough. He kicked my ass for like 2 hours so I was over it and wanted to get it over with. Took my time and my distance, used projectiles as much as possible, and cheesed attacked through the door. When you walk to the very back of room he resets to his original position at the stairs (I only did this once, but you could probably do this over and over so you can get a free hit multiple times).

Black Blade Kindred is an optional boss and you don't have to beat him, but I've been beating every boss I come across to fully experience the game.

Note: He gets stuck in the stairs in the beginning and I don't know how it happened, but I'm glad it did lol