Professor Tani created the original 8 Man cyborg technology. He oversees a cybernetics lab rocked by critical hardware theft, leading him to hire private detective Hazama Itsuro for the investigation. Following the original 8 Man's disappearance and implied psychological deterioration, Tani possesses the cyborg body and deletes Azuma's consciousness, though the exact circumstances remain undisclosed.

When Hazama suffers fatal injuries during the case, Tani performs an emergency transformation. He uses Hazama's biological template to reactivate the 8 Man unit, resurrecting him as the new cyborg entity. Tani advises Hazama to adopt a detached persona, suggesting he consider his former human identity deceased to manage the psychological duality of his existence.

Tani develops the specialized serum essential for 8 Man's cybernetic functions. This "Super Serum" contrasts with the unstable "Psycho Serum" used by criminal cyborgs, enabling enhanced capabilities while minimizing psychological degradation. To further ensure stability, Tani implants behavioral circuit breakers designed to suppress human emotions and prevent uncontrolled rampages. However, Hazama's intense trauma and rage can override these safeguards.

Tani maintains ongoing oversight of the new 8 Man, monitoring his missions against cybernetically enhanced criminals. He provides technical support and observes the integration of Hazama's personality with the cyborg systems, particularly noting instances where emotional triggers compromise operational protocols. His methodology involves significant ethical compromises, including memory manipulation and psychological conditioning, to maintain 8 Man as a functional weapon against urban cyber-terrorism.