Taki Haishyo commands Japan's Special Security Force, a government agency operating outside legal constraints to counter escalating terrorist threats. He leads a specialized unit authorized to eliminate the communist radical group Red May using lethal force when required. In this capacity, he issues operational orders to field agents Angel and Raiden.

His decisions prioritize mission success, including authorizing extreme interrogation methods against captured Red May leader Tachihara. This interrogation inflicts severe physical trauma on the detainee. Taki possesses awareness of the Hunters—psychic bioweapons deployed against the terrorists—and their link to a wider governmental conspiracy. He initially pursues an alliance with them despite inherent risks.

During the final story arc, Taki confronts Governor Maisaka, the architect of both the terrorist crisis and the Hunter program, inside police headquarters. Taki sustains critical gunshot wounds and is incapacitated, seemingly left to bleed out. Despite his grave injuries, he successfully plants an explosive device disguised as a tape recorder within Maisaka's escape helicopter. This bomb detonates later, eliminating Maisaka and his associate Nogawa. Taki exits the building before the explosion, though his ultimate physical fate remains ambiguous in the anime.

The manga presents a divergent outcome: Taki survives the series' events and joins the final confrontation against the conspiracy alongside other survivors. His role remains consistent as the commanding officer coordinating the Special Security Force's efforts against both the terrorists and the corrupt government figures manipulating the conflict.

His portrayal centers exclusively on his function as a high-level strategist within the security apparatus during the depicted crisis.