Darkwater Source (Object)

Generates, or simply opens a door for, . Killing them is great XP, and also rewards a .
This strange magic circle can be found in many places in :
*Right by the . () Level 20 
*In the goblin-controlled area known as the Goblin Farm, right by the water. () Level 30 Elite 
*Near the pirates by the gateway to . Level 40 Elite 
*In by the pond south of the Zurhidon Camp. Level 50 Elite 
Generally, only one circle will be producing at a time. We do not know what closes one and opens another.
This is a part of the Chaos Vortex event, which was introduced early in Chapter V: The Fires of Shadowforge. While this part is around level 20-50, the Chaos Vortex event is geared towards players at or near level 72.