```
"Boom... boom... boom..."
The deep rumbling spread in all directions along the stone surface.
The feedback from the spell reflected the density of the rock and soil energy, weaving an indistinct topographic map in Noland Lee's mind.
The dense network of tunnels resembled a spider web, each connected to several others, forming a hair-raising complex network.
In the distant tunnels, it seemed like something ominous was lurking, disturbing the rock and soil energy around it.
The vibration caused by the "Earth Energy Detection Technique" attracted these ominous things.
They began to approach the source of the vibration.
Noland Lee, through the changes in the density of the rock and soil energy, detected the presence of these things.
"Nolin, prepare for the enemy. Approximately 30 hostile unidentified creatures are approaching us, estimated to appear before us in 3 minutes," he ordered calmly, then added a few more instructions:
