The mysterious and deadly water that covered the world at the same time the Powerful but broken creatures, enslaved to keep mankind aliv... appeared, four hundred years before Harry Iskinder is the main character in the book, The Sunder... Iskinder came onto the scene.
It covers the whole planet apart from small islands, tufts, and landfall.
It kills in a frightening way: if a human r animal 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.
Note: if you’ve read The Sundered, feel free to jump on over to A character mentioned in Love Makes Whole, a collection of .... If you haven’t read the book, don’t. You’ll regret it otherwise.