It is one of the areas of the Rotten Blood Quest. The creatures here deal 3 different elemental damages: Energy, Physical and Ice, while being sensitive to Earth, Fire, and Physical.
Creatures in the area can put a Darkfield below characters. It can be compared to a Fire Field but it deals considerable Agony Damage instead. A darkfield can only be destroyed through Destroy Field Runes, but will always inflict damage on the initial target.