Ravening heart

A ravening heart is a ghoulish artifact extracted from a Beast of Bruada. These tireless killing machines of the Mother of Monsters are hunted for their hearts, for they continue beating long after the creature has been slain and can be utilised for a variety of purposes.

Properties

When extracted from a monster's chest, a ravening heart will keep beating until it is overtaken by rot or it dessicates and destroys itself with the beating motion. If preserved in embalming fluid or other such substance which protects the heart from rot, it can last for months or potentially years with the proper care and maintenance.
The presence of fresh blood excites the ravening heart, despite the lack of any present olfactory organs. This property of the hearts can be utilized for momentarily greater output, but it can also destroy whatever machine is connected to the heart if the increased output is not accounted for.

Uses

For much of history, Beasts of Bruada have been a blight on the civilized kith of the world, prowling the borderlands of ancient forests and forbidding wastelands. Even after the beasts are felled, their hearts continue beating in their chests, pumping long after the last drop of blood has left the body. The bodies (and the ravening hearts within) have customarily been burned out of caution, to make sure that the beast does not rise again to plague the community.
It was only in the recent decades that certain enterprising individuals began to experiment with uses for these unholy organs. They discovered that by connecting the heart to tubing filled with a saline fluid, the hearts could be used to circulate the liquid and power machinery through hydraulic pressure. The bigger the heart (and the creature which bore it), the greater the power output. Small or weaker hearts could be used in conjunction to power a grain mill, the hammers of a forge or other such household utility. A sufficiently great monster's heart could be used to power a heart engine, a hypothetical evolution of a far more ancient invention, the minecart.

Controversy

The grotesque nature of ravening hearts and the machines powered by them have faced plenty of vocal opposition throughout the years. Opponents of this technology claim it is akin to the savage blood rituals conducted by followers of Bruada, who are rarely welcomed within civilized society. Others claim the technology is dangerous and unpredictable, describing visions of demonic engines of steel and blood.