Prison of Souls

Olivia walked around the house closing windows and extinguishing lights. The kids and her friends gathered slowly at the table. With the windows closed there was no light except for the lamps spread about the house and she was putting those out too excepting the one she carried and the one she had left on the table. Like moths to a flame, they went to the table to sit in the little bit of light remaining as she slowly made her rounds entombing the house in darkness.
Finishing she walked slowly to the table and and set her own lamp down before cupping her hand around the top of the chimney and then blowing it out as well. The dim light of the single lamp just made enough light for them to see each other well. It was a large table, made for a halfling family to gather around.The result was perfect even with their low light vision the single lamp only let them see the people at the end of the tables silhouette and those closest to the lamp could only really make out their faces which distorted in the shadows thrown by the flickering light. Still standing she turned her back to them and then walked to the single window in the dinning room and worked at the latch until it released. This window was so seldom opened, her mother hated the view. The latch finally released and Olivia stepped back and let the distant lights of Chitzen Itzka glimmer in the room.
Several of the younger cousins and the various kids she was babysitting tonight looked out the window as she backed away from it. The home they lived in had been built by the captain of the prison guard many years and owners ago. The window had let his family see if any alarm lights were lit. She also imagined that it let the captain keep an eye on the place when he did have time to spend with his family. She didn't really know, no one did to her knowledge these days. Turning from the window she sat down so the far away prison lights illuminated her sitting in front of the window at the head of the table.
"While most people know that Chitzen Itzka, the Prison of the Lost, is at the center of our fair city and is in many ways its livelihood... What most people don't know is how far the prison goes down," she let her voice trail off for a moment. Letting the kids think of the dark pit that surrounded the prison on all sides and how the tower structure seemed to disappear into the darkness beneath. "And... what is really on the lower levels. Well, tonight... I will pass this knowledge on to you, as it was told to me when I was young. This secret has been passed along just in case its needed for years. But you have to promise that you'll keep it to yourself until it's your turn to pass the secret on to someone younger." She turned her head in an exaggerated manner making sure that they would know she was looking at each of them in turn as if she could see in the dark. It would make more of an impression, or at least that is what she remembered when she was little and her cousin had told her.
The story is passed on from child of the walled city to child and in many cases from parent to child on a night when they have been naughty and the parents was to get even by keeping them awake for a few hours so that they can sleep in the next morning. Interestingly the story from house to house is almost exact, giving credence to the idea that it might not be a story. Barring a few adjective changes and words the tale goes like this:
The taller races have always brought only the most dangerous and deadly prisoners to Chtzen Itzka, the difference between the height of the prisoners and the citizens of the city being one of the many ways that it was kept more secure. However some of the prisoners over time had proven to be so dangerous and cunning that they kept managing to escape their cells and attack guards even if they never managed to escape the prison. So after time when the guards wanted more money for keeping these deadly criminals the warden sent for a sorcerer and a bard. The two wove their magics together and created the lowest levels of the prison which were near endless. They would expand and the magic would warp the area around the prisoner to form portals to the places they were most destined for.
The lowest levels were filled with nightmares and the denizens of the hells sorcerously bound to the area that worked as a nebulous portal. Deadly prisoners would simply be taken to the door that leads down and then pushed through to have the door closed behind them. Since prisoners that were that dangerous were rare many who stayed at the door to try and attack the guards would perish from hunger or thirst before the door would be opened again. It is even said that many of those who died cannot find their way out still. Thus their souls remain lost in the dark halls of the prison, haunting it and seeking a way to the afterlife before they fall prey to the demons that their own evils and the evils of those who came before them called forth from the labyrinth. 
The true horror of this exile though was something unanticipated... not all of the prisoners were male or female and rumor had it that some of the fell creatures and even the prisoners who were mean enough to survive among such foes had children in that forsaken place. Many of these were part demon of some kind or even part nightmare. These dangerous offspring would rarely grow into adulthood but those who did were true horrors to be hold, deadly beyond compare. But trapped, in this ever shifting prison with only evil for company.