Unlike what you would expect from a chaotic city constructed in a place of slaughter like the 4th layer of Abyss, Evil City was full of order.
Demons were using every second of their day to increase their strength and learn the army formation taught to them by their Demon Lord.
Evil City could be considered a heavenly place for lesser demons. The amount of Abyss Aura and natural energy in it was hundreds of times greater than what you would find outside, and there was even an increase in the density of Origin Power.
There was an evil and dark aura that covered every corner of Evil City. It would not be wrong to call it the strength of the Infinite Layer of the Abyss.
Those inside this horrible aura only needed to close their eyes to see the monster controlling it. He was a five-meter tall white humanoid that could incite fear even in the heart of killing machines like demons.
