Purgatory City has neither city gates nor biological mimicry devices, because there is no need for them.
Xiaoliu's Eternal Ice Realm leaves behind its Calamity-grade aura, which, to a certain extent, is far more effective than any biological mimicry device.
Although this blighted land is harsh, and people frequently freeze to death along the roads, it can also be considered a forbidden zone for Desolate Beasts, with very few daring to raid it.
Chapter 334