Under the shroud of Purgatory Light, Purgatory and the Sky Pond are vast with inexhaustible top-quality spiritual medicine and minerals.
This allows Purgatory Demons to exchange through the Longevity Association for various mecha, combat robots, armored cars, plasma cannons, close-in weapon systems, as well as tunnel boring machines, rock drilling machines, engineering robots, and other war and engineering machines.
Even the armies of the Great Song have to follow suit and purchase all kinds of war machines from the Heavenly Demons.
Previously, the wars between Purgatory and the surface were an endless tug-of-war inside some existing tunnels.
But now both sides are trying to dig tunnels to attack from behind, so the battle lines are getting longer and wider.
