Takaaki Koshiki, a civil servant and system designer, worked on a joint health-welfare project under prominent politician Munei Ito. After distinguishing himself, Koshiki received reassignment to the project and covertly built his own infrastructure into its design. This system was engineered to abduct children classified as at-risk, placing them with elderly participants enrolled in the “Noble Rot Senior Citizens” or “Old-Age Kifu” program. These seniors, linked to a health care monitoring network that left them nearly comatose, would bequeath their assets to the children upon death. The children were then transported to secret educational facilities within the Seishomin Welfare Center.

Koshiki died under mysterious circumstances from an illness at home. After his death, his remote-controlled body became involved in a conspiracy uncovered by Public Security Section 9, suggesting a hidden “Puppeteer” entity was acting in his name. It was later confirmed that the real Takaaki Koshiki had used a prosthetic body. Hired by Munei Ito, he built the Solid State system and ultimately committed suicide.

The Puppeteer, who assumed Koshiki’s identity, was discovered to be a fragment of Motoko Kusanagi’s consciousness that had merged with the collective consciousness of the Noble Rot Senior Citizens. This collective consciousness, termed the Solid State Society, used the healthcare network to form a rhizome-like entity. The Puppeteer employed Koshiki’s hub-cyberbrain to crystallize this rhizome. An alternate theory proposed that the Puppeteer may have personified the collective consciousness of the elderly in the program. The ultimate identity of the Puppeteer was left unresolved, and the incident was officially recorded as a political scandal.