The mysterious and deadly water that covers the world and appeared at the same time the Sundered Ones appeared, four hundred years before Harry Iskinder comes onto the scene.
It covers the whole planet apart from small islands, Tufts, and Landfall.
It kills in a frightening way: if any living thing other than a Sundered One touches it, they are immediately pulled into the water and down. The victim cannot be saved; not even Sundered Ones can bring them back.
The only time it’s safe to touch black water is if it’s been separated from the main earth-wide body of water. Buckets are often used for this, though everyone tends to prefer making Sundered Ones fetch it – since they can touch it without harm, for reasons unknown.