The Winterfall Firewater was made by Xandivious and given to the Winterfall tribe to corrupt them. It`s mainly made of elements from corrupted creatures in Felwood. They and the firewater are transported by some Winterfall Runners between Felwood and Winterspring. To purify the Firewater from the toxin they need the water of the Frostfire Hot Springs. It seems to cause paranoia and make you addicted to it as High Chief Winterfall is