Conjuring the Kishin

 A Kishin is a being created from the over-hunting of a large amount of pure, good people and human souls and possesses dangerous destructive power.

After the events of Death becoming wary of Asura's actions, he stripped Asura of his skin and sealed his soul and body within it by making a sack. Death did this to contain all of the Madness that the Kishin Asura emitted and his soul and body. As a sacrificial consequence, Death had to implant his soul into the exact spot where he made the seal, making his movement limited to what later became to known as Death City. 

Madness Wavelength (Kyōki no hachō): Kishin possesses this particular wavelength and the capability to wreak havoc onto the world and put it towards potential annihilation, this extreme level of power requires a true death god to intervene. Due to this high level, their madness wavelength also gives birth to unique forms of madness. 

Absorb (Kyūshū): Whether through being a demon weapon or an ultimate weapon meister type, Kishin possesses the ability to consume souls.

In a way, there is a  Kishin energy definitely growing and flowing around and slowly taking over this Planet Earth.