Within the Praxim of the Ancients are many such pools of purity, magical waters said to emanate from the God Tree itself. These holy waters are capable of "purifying" those who come in contact with it of magics hostile to the faith of Yevna. Such pools are potentially deadly to the Rasa as spirits, and serve as a poison that corrodes their existence.
It is believed that similar pools of purity exist among the Changelings; these liquids have psionic properties, and sometimes shapechanging effects. Notably, the vales of the Faunlin possess pools of purity made of mud that dispel Rasan spirits from those possessed.