I've never written a review for a DLC, but here I think it's warranted.
This "Crucible" mode, is what every ARPG should have.
You kill, loot, rinse repeat. It's the very essence of an ARPG, packed into one gamemode.
You can test your build extremely well, or just enjoy the carnage.
10/10 DLC, tons of fun.
Note: You will need to reset your instance every now and then, because the loot doesn't disappear, and there will be a crap ton of items on the ground after a while.
If you enjoyed your time in Grim Dawn's campaign, get this immediately.
Very highly recommended.