Not that long ago, a pack of Gargoyles returned to a place of spawning. When they returned, things had changed. Nestled in the rocky hills was a city of some strategic and economic importance. The Gargoyles were slightly perturbed with these interlopers sitting on their holy ground, though they did provide some taller places to perch. After a short debate, the Gargoyles decided on a compromise, they would take a small nesting area, that the natives had already walled off, and leave the rest for the fleshy things. It will only be for a few decades they thought.
That was many decades ago, the new eggs will hatch in just a few more.
The Grey District was a walled off inner district of the prosperous city. It several guild halls, two smitheries and glass works with tall chimnie, and held a temple with a clock tower. One night, the Stone Gargoyles swooped down and killed all those on the street, and took to killing those in houses whos windows spilled out light onto the street. The next day, the few survivors scurried their way out of the district. Those who made much in the way of noise as they scurried were attacked. Humans outside the walls were left unharmed. (Except if they made an exceptional amount of noise, then the gargoyles would take to wing and attack the transgressor).
After several attempts to repulse the Gargoyles (who are nearly immune to magic, have rock hard skin, and superhuman strength and speed), it was decided to cordon off the area. Laws were also passed about how much noise one could make in the adjacent districts. The district wall was painted with a gray stripe, similar to the one that marked plague.
Of course some people would not leave the district. Those Grey People as they were called never went out at night and blacked out all windows so they would not shine light at night. They are a quiet folk, realizing that a good deal of noise will bring sudden death from the ever observant Gargoyles. They have a language of gestures they will use for most things. Soon the poor and a few others trickled back into the district. While not as prosperous as it once was, it is a living district once again.
One thing the peoples of the city have noticed, that night time theiving has drop significantly. The Gargoyles seem to be "picking off" the transgressors no matter where they are in the city.