Matron
The pinnacle of achievement in the Age of the Great Morthificers was Matron, a being of horrific stature and appearance, with the mental capacity to imagine new forms of automation, the physical capacity to create them, and the moral capacity to decide why.
One might expect that the story of Matron is one of the machine growing too smart for its master. The truth is that Matron served the morthificers to the bitter end, even as they fell to their own greed, and the predations of other less peaceful beings and societies (the morthificers were mostly interested in peace, medicine, and defeating death), she grieved and sought their preservation.
As the last of the morthificers died and was forgotten, Matron was left alone in her dark hall, and over millennia her vast ever-going brain worked on ways to alleviate her own loneliness and serve her masters still.
Who knows what conclusions her ancient logics led her to. What we know is that she set in motion the old morthiens. These ensouled beings who stood in dark places, guarding old troves, now rove the yondering with real purpose, collecting “material” from the bodies of living creatures.
What’s she building down there? Only one way to find out.