You assemble the troops and complete a quick head count before departing. As you are about to call out the signal to march, you notice the rear guard, some way off and frozen stiff with horror as they stare down a side alley. Suddenly, a towering bank of pitch-black fog bursts from between the buildings, crashing over them like a wave. The men disappear under a tide of darkness, utterly consumed.

You have only seconds to react as the deadly black fog churns up the street toward you.