All of North and South America have fallen, Europe and Africa are desolate. Large areas of cities have been completely abandoned, leaving only desolate concrete forests.
The Frost Serpent went to Northern Europe, the Darkness Serpent entered the Middle East, the Thunder Serpent rampaged in many island countries of Oceania. Only the Light Serpent was firmly repelled by Lin Ning using the Taiyin Su Ming Sword at the western border of the Lu Country, preventing it from penetrating the populous heartland of the Central Plains.
Now, the Lu Country in East Asia is likely the only place in the world not extensively ravaged by the serpents devouring mortals, and it's where the seeds of modern civilization are best preserved.
Lin Ning's return as the Taiyin Sword Master has greatly inspired and invigorated both the government and the populace. At the very least, we now face the Light Serpent with some strategies instead of complete helplessness.