You will need to kill:
The Throne of Elements is just north of Garadar on the other side of the lake. At 33, 50 right in the middle of the lake is where you will find Watoosun's Polluted Essence. The Lake Surgers are all over the lake itself and hard to miss.
Watoosun was able to shed the stink of corruption; but in doing so, created a twisted spirit essence. A spirit essence composed of the vilest corruption found amongst the elements!
You will find this polluted spirit of the swamp southwest of here, hidden in the depths of Lake Sunspring.
Find and destroy the polluted essence of Watoosun and any corrupt offspring that it may have created.
The elements sang of your victory the moment the disturbed essence was destroyed! The Earthen Ring thanks you and wishes for you to choose a reward.