Main City Zone, inside the experimental factory.
Steel machinery was everywhere, producing and transporting various types of weapons and armor, and people!
At this time, a group of people walked on the steel bridges inside the factory, the middle-aged man leading them surveyed his surroundings as machines operated nonstop.
This was the true Core Land of the Underworld.
As they moved forward, there were heavily armed guards on the other side of the steel bridge, as well as formidable armor—like a moat in the sky—making it impossible to force their way through.
Ahead, there was "the only" passage to the world above.
After crossing the steel bridge, they continued forward and came to a stop at a certain location.
In front of them, there were many sealed elevators transporting goods.
This area was heavily guarded; it was the true secret place of the Underworld.
The passage between the surface world and the Underworld.
Both people and "goods" were transported from here.