In connection to the producers fantasy book that is still in the works called "Aqualon - Rise of the Broken", Tales of Chaos City is a former technocrate city that has been overtaken by technamagix gone awry (technamagix is the fusion of magic and technology and is often referred to as souled-technology), a place where people are used up like resources until they die or kill themselves by a living city that is hungry, always hungry.
The setting is that of a living high-tech steampunkesque city and the extreme exploitative industrial structure of the city exudes great amounts of toxic gasses and particles into the atmosphere where they gather in a thick ashen cloud-layer.
The series starts with a a medieval type ballad. A black and green radiating city that inhales dreams and exhales corruption. That is so rotten that despair spreads under its people's skin like black iron root.
The metric choir is a representation of the drone faction. The twist is that even though they call themselves 'metric' the 'metric choir' there are several rhythmic anomalies in the singing, because humans are not meant to be uniform and the genetic alterations are deteriorating to their natural faculties.
The fourth song of five of the 'Tales of Chaos City'. Warning: This video contains strobe effects
Sometimes enough water condenses into that cloud-layer to cause rainfall. The water that finds its way into those clouds reacts with certain particles producing soot and acid which then pour down in the form of liquid precipitation. During those times the buildings take heavy damage and need to be repaired afterwards, naturally all people on the streets would melt in the acidic rain, so the city makes sure they have been directed to sheltered areas. However sometimes a few of the isotope incubators manage to escape into the open and finally be free of the horrible lives they lead as they melt in the rain and die.
Redemption circles around the peoples fears that the way they have been abused, as gene-manipulated batteries and such has made them somehow damaged and their souls unworthy of saving. Thus the main-line is 'Will god still take me when the devil's done with me?'
With this song the Tales of Chaos City come to an end.