God and Satan have been fighting over souls since mankind first sprung from the earth and thedarkcity is where those poor undecided souls go while their fate is decided. Fraught with crime and high-rise buildings, successful business and junkies on the street corners- Dark City appears like any other large city. Dark City is very large and can accommodate a multitude of people from all walks of life. However, those who wake up in Dark City cannot leave Dark City. A large fence surrounds the perimeter of the city and anyone trying to cross the threshold will be in an immense amount of pain for some time. The only way to leave Dark City is for your immortal soul to have moved on permanently to the Gates of Heaven or the Pit of Hell.
All souls are created equal in Dark City. In other words, millionaires will lose their millions. Although any personal attributes (such as superpowers) can be carried on to Dark City, any materialistic goods will be lost. The only thing a soul has is the apartment they woke up in, and the clothes on their back/money in their wallet. Cut up your credit cards from the world you came from, they won't do you any good here.
Souls do not know that they are dead, nor can they find out. If any soul were to discover the truth, chaos would reign, and the debate would be considered a forfeit. The universe as a whole would be destroyed. Souls can be harmed, and die in Dark City just as they could in their home world.