Two men born to fight the same monsters realize too late they're fighting for opposite sides. Zetman doesn't ask which one is right, it just shows you the cost of being certain. By the time you understand what the Amagi Corporation actually built, the show has already destroyed the friendship that could have stopped them both.
Jin Kanzaki carries a terrible secret: something inhuman lives inside him, awakening when violence demands it. His transformations into ZET grant him power beyond human limits, but each shift tears him further from his own humanity. Across the city, Kouga Amagi fights monsters with cutting-edge technology and unwavering conviction, unaware that his own family corporation birthed the very creatures he hunts. These twisted abominations, called Players, emerge from shadows to feed on human flesh, and both men find themselves on a collision course against them. When Jin and Kouga finally meet, their opposing methods clash hard. One relies on savage instinct, the other on reason and engineering. Both believe they fight for humanity's survival, yet their paths seem destined to destroy each other first. As bodies pile up and the Player threat grows, the line between savior and monster blurs dangerously. Their choices will determine whether mankind finds salvation or extinction.