The mountain range where the Evil Spirit Valley was located was very wide.
As it was located at the east side of the Catacombs world, this mountain range ran from north to south. It was basically the end of the east, isolating the Catacombs world. Very few people could pass through this mountain range to reach the back.
According to their estimations, this mountain range stretched for tens of thousands of miles from north to south. The most dangerous area was the circular area in front of him that was thousands of miles long. This was the especially dangerous place that they had concluded. It was the easiest to see the Evil Spirit Valley.
The Evil Spirit Valley got its name because the people who escaped said that the valley was filled with dead spirits. These spirits kept wailing and hissing, tearing every inch of flesh off the people who entered.