People who follow a school of unnatural, science-based druidic magic. Just as druids attune themselves to natural spirits (animal, mineral and plant), chaos druids attune themselves to unnatural and chaotic spirits (unexplained, mechanical and otherworldly).
The transformational magic they use is based in science, created by the scientists and wizards of the overpopulated and poverty-stricken cities that wished to be able to attune with spirits and change their forms just like the druids. Without a connection to natural world, they instead used a combination of machines and magic to fuse with the unnatural spirits of the cities.
The magic itself is incredibly unstable and difficult to control. Many of its practitioners lose their minds or make a mistake and kill themselves trying to fuse with something.
Little is known of the origins of the machine druids but the records of them only date back about a hundred years.
Frowned on by the druids of the Outer Reaches.