The Witnesses of the Last Upload are a doomsday cult of approximately 1,200 adherents who believe that a specific individual — a neural engineer named Dr. Vikram Nakamura, who disappeared in 2191 — successfully uploaded his consciousness to a hidden server somewhere in GLMZ's deep infrastructure, and that he will 'download' back into a physical form when humanity has sufficiently prepared itself through augmentation and moral purification. They are, in essence, an apocalyptic movement waiting for the second coming of a man who probably just died in a lab accident.

The Witnesses practice extreme augmentation — not as worship, like the Silicon Apostles, but as preparation for the Download. They believe Dr. Hesse-Nakamura's return will require his followers to serve as 'receivers' — their BCIs acting as distributed nodes in a network that will reconstitute his consciousness in the physical world. This means members maintain their BCIs at peak specification and undergo regular 'alignment' procedures that adjust their neural interfaces to match what the Witnesses believe are Dr. Hesse-Nakamura's specific neural patterns.

The cult is small, intense, and operates with a paranoid security culture that makes infiltration nearly impossible. They believe the corponations — particularly TESSERA, which employed Dr. Hesse-Nakamura — are actively working to prevent the Download because a successfully uploaded and downloaded consciousness would prove that corporate control of augmentation technology is not just exploitative but spiritually criminal. This belief system, while almost certainly delusional, keeps the Witnesses loyal, secretive, and prepared for a confrontation with corporate power that they consider inevitable.