Automated builders
Automated builders are colossal self-replicating machines that the Framework Assemblers designed to repair, improve, and extend the Citadel under DAAT's authority.
After the Derailment, surviving builders became locked into the last instruction they received. They continue expanding without supervision, adding new structure around damaged systems and inhabited regions. Some are classified as immense golems; others have degraded so far that scholars call them ghouls.
The Citadel still repairs and extends itself. Colossal automated builders that survived the collapse became locked into their final instruction—repair, improve, expand—and now execute it without restraint. New architecture grows around old systems without safe oversight, turning expansion into something closer to uncontrolled biological growth.