I will just say this much I have been camping this nm off and for years I am currently 0/63 on him.....(Jesus SE a little break here)
Here is info I can give if it helps anyone.
I always go straight to the room he pops in kill the Cutter then run down the hallway kill the cutter in the hallway and go in first room behind door and kill the cutter in that room. Roughly 16 min repop on the cutter tons.
My average for him is roughly 1.5 to 3 hours to make him pop once I get there I have never waited more then 4.
He is quite honestly a Joke to fight. He "Maybe" gets 2 hits on my ninja if I not paying attention to shadows but other then that wont hit me period. His 2hour on the Other hand just like everyone says is ********** 1 day it will hit you for 10 damage and the next time 1 shot you. I have tried every tech to try and make damage less but nothing seems to be a perfect fix to the problem. You pretty much have a 50/50 shot that his 2hour wont wipe you I have died easily 20+ times to his 2 hour.
All and all easy fight if u wipe just have rr up. Get back up heal and go fight em again he wont do Mijin twice to you. And with his HORRIBLE drop rate you shouldnt have to worry about 3 or 4 people stalking to get claim after u die. I wish all of you Luck with him. He is my Bane (Conquest) of ff that i must do before I ever quit.
Dont even bother calling one of you 75 thf friends to help with him. Sozu sarberry seems to be anti- treasure hunter. But good luck all the same :)