These are the prisons of the souls of the damned. After Kratos is defeated by Charon and thrown into Tartaru (Location) and all of this jails are led and manage by Tartarus (Primordial God), he awakens and finds himself chained here. He then breaks free of his shackles and finds a way out. The whole area is filled with shackles and chains, and many other prisoners can be seen chained to the walls. After the prison, Kratos ends up in the Temple of the Gods which lead to the crypt and the Shackles of the Titans.