The underground fighting arena is located beneath the Seven-Ring Yunshan Tower.
This is a comprehensive underground structure, which can be regarded as an independent underground building.
In fact, the entire Mingjing City has a super complex of underground buildings.
Most of these underground buildings were built by the Alliance. For hundreds of years, the Insect Race was fierce, so most of the human buildings were constructed underground.
After expelling the Insect Race, humans returned to the surface. Most of the underground complexes were also abandoned.
These underground complexes slowly gathered many criminals, cult followers, and so on.
For hundreds of years, the underworld has become independent, not bound by Alliance laws.
According to unofficial Alliance statistics, the underworld has at least millions of people. Most of these people have no Alliance identity, with no data on the Celestial Net.
