Unlike many of the ancient ruins, Mad Zone is not crawling with dangerous life forms. Instead, it is crawling with dangerous live metal. Before the Cataclysm, the city was the site of a robot production facility. The plant was presumably destroyed, although nobody has been able to prove this. However, the robotic offspring of the factory still wander the streets. There have been sighting of all types of Live metal including street cleaners, Police Robots, and construction machines. Some are at best neutral toward living creatures, and many ae hostlie.
There are secretive life forms that successfully survive the streets of Mad Zone. Archivists and the Followers of the Voice are particularly enamored with living here, even though they must hide from the live metal to survive. Since live metal do not search or even enter many of the smaller buildings, animals and even people eke out a meagre existence. The sentients tend to be Tech Level 1 or even Tech Level 0 societies.
Mad Zone is the only ancient city in Meriga that is still growing. The live metal have spent the last few centuries rebuilding the city. Since ther are not very many of them and resources are scare, the process has been very slow. So slow, in fact, that they frequently have to go back and restore sections thta they had restored decades ago. They have approximately a third of the city rebuilt. What they will do several centuries from now when the project is complete is anyone's guess.