This black ooze goes by many names. Some patches of it display a form of sentience and attack other creatures.
The influence of this sludge has a disturbing affect on others. During the war entire villages drowned themselves in the sludge, walking mindlessly to their death. Some creatures find themselves physically or mentally mutated by the ooze. It serves as both defense and offense to the armies of Bane.
Certain individuals have learned to harness the power of their mutations. Others have taken to worshipping the ooze as a deity in its own right.