by Pilgrim34 Mon Apr 22, 2013 6:42 pm
I think they're essentially corrupted humans who have been down in the Chasm for a considerable time whose humanity, like that of Manus, has gone wild.
They don't come across as particularly "malicious" enemies so maybe it could be that they are attracted to any humans that are more "intact" ie the Chosen Undead, but in their corrupted state their presence and aura are incredibly damaging to humans (similar to the spell description for dark fog).