I tried this. He doesn't chase past the first small doorway in his area, he just resets back to the place he initially spawned. I even tried taking off the blindness ward goggles, letting him blind me and then navigating back there and he still gave up, even when his dogs continued chasing me. Is there a way to trick him into continuing past that point? Maybe I need to path it differently, running down the left wall and continuing around towards the door?
I probably should get a really good ranged weapon and give this a shot. I tried it with returning shuriken and they hit him ok for damage but his rays are hard to deal with and it's easy to take a lot of damage popping in and out of view to throw. The time I killed him I used the Silver Flame trinket to absorb his level debuff on the way in and then got some good damage on him fast and dropped him. I highly doubt I could repeat that method except by random luck.
I'll give this a shot.