When they first entered the Deathzone, they were greeted by thick jungle, black rivers, and cliff structures. The most 'open' field they encountered was the wide clearing where they faced a horde of hounds on the first day. The marsh, although 'open' in some locations, was also filled with tall, eerie trees jutting out of island formations here and there.
And so, when they faced this vast, vast field with nothing in between, they couldn't help but stand there dumbfoundedly. There were no eerie trees or tall cliffs except those behind them. It was just a plain empty field as far as their eyes could reach. Far, far away on the other side was a dark void that even Bassena's eyes couldn't see. It was more than two kilometers too, so his children of darkness couldn't try to see what was beyond.