I know there is a possible way to farm them with A/E with Shadow Form and Sliver Armor but could someone just help me out with the full build and strategy. I want to know this as I want to find out if it is worth getting my sin there.
Before you ask... I HAVE used the search and found nothing.
As to whether it is worth getting your sin there -
They do drop celestial weapons fairly regularly but most are high req or not max stats, even in hm. Also the koi scepters they drop produce a fair amount of steel. The vermin hides can be traded to a collector just past the portal at the end of the run for an easy source of free id kits. It is not my favorite farm spot but I run it once in a while for fun or if I'm low on ids. (I use A/Me for this one though as the A/E I was using was just a shade too low damage for my comfort and I had trouble with the boss)