Professor Tani is the scientist who created the original 8 Man cyborg superhero. His experiments transfer human consciousness into android bodies, a process that failed seven times before succeeding with Detective Azuma. After Azuma's unexplained disappearance, the city faces increased violence from cybernetically enhanced criminals using stolen technology derived from Tani's laboratory.

Tani hires private detective Hazama Itsuro to investigate the theft of cybernetic components. When Hazama is murdered during this investigation, Tani uses his body as a bio-template to create a new 8 Man, reviving him within the original cyborg body. This process requires Hazama to maintain his original human identity as cover while coping with the duality of his cynical personality and the emotionless demands of being a super-android hero. Tani provides ongoing technical maintenance and guidance to the new 8 Man, advising him to adopt a detached perspective on his former human life.

Tani develops specialized serums to stabilize cyborg functionality. While criminals use psycho-activated drugs that trigger insanity when combined with cybernetics, Tani creates a higher-quality "Super Serum" allowing 8 Man to operate without mental deterioration. He also implements behavioral safeguards to prevent emotional overrides during combat, including a circuit breaker. This safeguard proves imperfect when Hazama's traumatic memories bypass the system, causing uncontrollable rage.

Tani's actions reflect a consistent ethical stance toward cybernetic technology, contrasting with antagonists who weaponize his stolen research. His scientific expertise remains pivotal in countering cybernetically enhanced threats.