Itsurō Hazama operates as a private detective haunted by a past steeped in police corruption and personal loss. Years prior, during a drug investigation that exposed corrupt officers like Tony Gleck, his refusal of bribes led to his sister's kidnapping and brutal murder witnessed by him. This trauma ignited a violent quest for vengeance where he killed three crooked police officers and four members of the drug ring. During Hazama's pursuit of Gleck onto a train bridge, police intervened, resulting in Gleck being shot and struck by a train, presumed dead.

Hazama possesses a hard-nosed, direct personality, favoring casual interactions over formality. He accepts a case from Professor Tani to investigate stolen cyborg components, a case intersecting with Sachiko Yokogawa, associate of the original 8 Man. During this investigation, Hazama encounters Tony Gleck—now a cyborg—who inflicts fatal wounds upon him. Professor Tani salvages Hazama's body, converting him into the new 8 Man to replace the missing original. Publicly, Hazama maintains his human identity as a cover while functioning as an emotionless android crimefighter.

Struggling with his new existence, Hazama contends with fragmented memories of his human life, particularly his sister's death and his vengeful actions. His dual identity fuels internal conflict: the cynical detective clashes with the detached, superhuman enforcer. This duality intensifies as he confronts cybernetically enhanced criminals and navigates his residual humanity. His traumatic history with Gleck resurfaces, driving his aggressive pursuit of justice while forcing him to question how much of "Hazama" endures beneath the 8 Man programming. His development centers on reconciling past trauma with his present role, balancing vengeance against his evolving purpose as a symbol of order.