Land of the Four Heavenly Pillars.
Near the South Gate Pillar, there existed a city naturally formed by the forces of creation.
This city was called Yimu Immortal City.
The entire city seemed to have evolved naturally. From a distance, the walls appeared lush and verdant, but up close, they were a complex web of thorny vines. Ambiguous wisps of colored mist intertwined into intricate patterns, signifying that the city walls were in fact made of intertwining spiritual trees. And the mists were the accompanying spiritual light of these trees.
These had the effect of confining enemies, providing resistance, and serving offensive purposes.
Moreover, these spiritual trees could support and grow with one another, especially in the face of enemies, where they could even form powers akin to combination formation techniques.