River Isis

The River Isis was a waterway found in the realm of Heliopolis, in both the Great Wheel and World Tree models of the multiverse, that was named for the Mulhorandi goddess Isis.

Description
The waters of the River Isis were cool and clear. Uniquely, in the Great Wheel cosmology they were said to be tinged with a magic that prevented them from becoming polluted no matter what was put into them. The water was also said to act like holy water, but only while it was within Isis's city of Gizekhtet. If it was taken beyond the city, it would be normal water.

Geography
In the Great Wheel cosmology, the River Isis was said to run solely through the city of Gizekhtet, in the divine realm of the same name. In the World Tree model, the river was said to instead flow all throughout the desert of Heliopolis, irrigating the land and providing a source for all life in the plane. Along its banks stood the city of Thebestys and it passed through the city of Gizekhtet.