Argus, the glasswork sentinel.

The alchemists of the Crystalheim Foundry were losing everything to thieves who slipped past their guards in the night. Desperate, they turned to forbidden arts, melding living crystal with brass and steam to create the perfect sentinel. They fractured a single consciousness across multiple heads so it could see everything, while the translucent skin let engineers monitor the delicate clockwork pulsing beneath. Those brilliant blue lights pulse with their thoughts, flashing brighter when intruders approach and sending silent signals through the brass arrays in the walls. Now it waits in the vault's darkness, steam hissing from its joints as three minds share one purpose. The brass mechanisms tick like a heartbeat, marking time until the next fool thinks they can steal what it guards.