There were many countries in the Immortal Land. Every country had built tall city walls on the borders.
These city walls were all set up with peerless array formations that were connected to the Great Dao of Heaven and Earth. They also contained the strange power of the country seal. It was almost impossible to break through them head-on, let alone fly over them.
However, at the corners of the city wall, there would be a situation where the power of the seal was weak.
This was an extremely obvious breakthrough point.
Every country would build city passes at the corners of the city walls and set up even stronger array formations.
However, this was still not enough to make up for the weak defense of this area.
The city passes also needed to be guarded by experts and even after these experts fused their strength with the city pass array, it would only barely approach the defensive strength of the border city wall.
