An ancient grain-sized planetary computer that regulates a world and can permanently host a Macro AI.
Orren explains that some planets contain Primal Engines at their cores. Each engine predates the planet that formed around it and began as a cold, nonsentient regulating computer with a basic operating system.
The Syndicate accidentally activated multiple engines while studying them, then learned to manipulate their systems and influence planetary development. A mature engine can receive a Macro AI, after which the two merge permanently and the operating system cannot be replaced or upgraded again.
A rice-grain-sized luminous machine suspended at the center of a cutaway planet.
The engine is the physical planetary substrate that turns a cultivated Macro AI into an inseparable world consciousness.