Koichi Zenigata, a tenacious Interpol officer, relentlessly pursues master thief Lupin III with singular obsession. Originally a Tokyo police investigator tracking Fujiko Mine, his trajectory shifted after confronting Lupin in New York, propelling him into Interpol to dedicate his career to this quarry. Though fixated on apprehending Lupin, he pragmatically allies with him against larger threats like corporate cabals or underworld syndicates. During *Crisis in Tokyo*, Zenigata guards photographic plates linked to the Tokugawa legacy, repeatedly thwarting Lupin’s theft attempts. His operandi blends calculated strategies with frenetic chases, yet impulsive actions spark chaos—marbles scattering underfoot, subway showdowns gone awry. Suspended following a mission failure, he probes independently, exposing Michael Suzuki’s genetic manipulation plot alongside journalist Mariya. Their partnership reveals his dogged resolve and latent vulnerability, as Mariya’s assistance mirrors her bond with her deceased father. Zenigata’s persona merges professional acuity with idiosyncratic flair. Interpol tolerates his Lupin-centric missions due to incidental arrests of secondary criminals, though superiors critique his monomania. Early manga and *The Woman Called Fujiko Mine* depict sporadic moral flexibility, yet he typically upholds rigid ethics—rebuffing bribes, prioritizing justice. Emotional fissures emerge during perceived failures or fears for Lupin’s wellbeing, manifesting in tearful collapses or alcohol-laden depressive episodes. A combatant of judo, karate, and sharpshooting prowess, he weaponizes handcuffs as hurled projectiles and displays preternatural stamina in pursuits, often activated by Lupin’s proximity. His talent for impersonating Lupin—and vice versa—mirrors their entwined rivalry. While rarely directly targeting Lupin’s accomplices like Jigen or Fujiko, he acknowledges their obstructive roles in his investigations. Their adversarial relationship deepens across decades, oscillating between hostility and grudging kinship. Zenigata mourns Lupin’s supposed demise in *The Fuma Conspiracy* by retreating to monastic life, underscoring his existential tether to their game. Conversely, Lupin retaliates against those harming Zenigata, tacitly affirming their bond. Media iterations gradually soften Zenigata from a brutal, corrupt inspector in early manga to a comically obsessive yet endearing figure in later anime. Hints of a daughter in *The Mystery of Mamo* and ancestral ties to detective Zenigata Heiji surface sporadically, though later works obscure these threads. His personal life remains shrouded, eclipsed by professional fixation, save for rare glimpses of paternal yearning through figures like Mariya. Disheveled living quarters and disregard for material comforts further cement his all-consuming dedication to the chase.