Fate Wheel

Fate wheel, wheel of fate, fated gyre, the rotations of destiny, are all names for the same device. Used in Deorma, the wheels are a rather eccentric technology, to use the term very loosely. Most villages have one. Cities do not, for reasons that will soon become apparent.
To fight is a way of life in Deorma, in a more practical sense than the rest of the world which requires at least some reason for it, however superfluous. There are plans and plots and decades-long schemes that can all lead to a single battle. But in Deorma, they fight a lot. They fight outsiders, they fight other clans, and they fight each other. But when this all becomes a bit personal, and the neighbors are a bit tired of the battle, they turn to the fate wheel.
It is, in fact, composed of several wheels, and its internal mechanisms have even more. And when these wheels turn, monsters are produced for the locals to fight. The device works as a generator, producing realistic creatures to battle and cause damage to the villages. They are fought and defeated, and everyone goes home happy. Including the garbage collectors, who are able to simply dump waste products into the machine as fuel.