Chemical weapon spewing blight drone

This version of the blight drone daemonic war engine was often accompanied by war flies and spewed chemical gas of a deadly necrotic agent that choked it's victims to death and resurrected them as pox walkers.  This is in addition to it's already deadly firepower and combat capabilities.  The imperial high command grew increasingly alarmed as these daemonic engines continued to evolve into nastier killing machines as the Stygian Wars dragged on.