Fujita Zenkichi works as a photographer and partners with Sakon Tachibana in investigations, displaying proactive enthusiasm for his craft. His dedication stems from a powerful drive for justice, influenced by his father—a fellow photographer who died on a Vietnam landmine. This event motivated Fujita to use photography as a tool for pursuing justice.

He appears exclusively in the series' fourth, seventh, and eighth mystery arcs, accompanying Sakon to offer direct assistance, particularly during confrontations with killers. Despite his passion, Fujita frequently forgets to take photographs roughly half the time.

His connection to Osaka, historically named Naniwa, is implied through the manga's final case title, "Naniwa Photographer Bible Hell." Early manga chapters referenced him by the blended monikers "Fujikichi" or "Fujiyoshi."

Functioning as a support character, Fujita aids Sakon and Ukon during their travels across Japan, contributing practical help in solving crimes alongside Sakon’s aunt Kaoruko, a police detective.