The Underground Ghost Market was not situated on a flat, horizontal plane. It consisted of a dozen waterfalls, tens of river sections, and hundreds of caves of various sizes. Due to the differences in elevation between the tributaries of the Dark River, the entire Ghost Market was divided into several layers. Some areas were only accessible by bamboo stairs or by diving.
Without familiarity with the terrain and a guide's directions, it was easy to get lost in the sunless Dark River system and never find a way out.
No wonder the Yu Kingdom's Court and the garrison couldn't eliminate the Ghost Market here. The underground Dark River extends in all directions, with countless secret passages. It's hard for a large army to enter, and even if they do, the people in the Ghost Market can quickly evacuate and move to other Dark River systems.
