Enzyme is a special breed of Zoanoid designed for a specific purpose: destroying the symbiotic alien armour known as the Guyver. Following repeated failures to capture the Guyver, Richard Guyot - commander of Cronos Japan - ordered the development of a new type of Zoanoid designed specifically for killing the Guyver, and used the Japan branch's former head Genzo Makishima as a guinea pig. The development was incomplete, but successful. The first Enzyme model succeeded in killing the Guyver 1 and removed its control medal. However, Guyver 1 was resurrected by the control medal, which used traces of Sho Fukamachi's DNA left on it to regenerate his body. With the threat of the Guyver increased and the destruction of its Japanese branch, Cronos renewed the development of the Guyver-Killer class and created new Enzyme models to combat the Guyver.
Genzo Makishima was the head of Max Pharmaceuticals, actually the Japan branch of Cronos. He usurped control of Max from his brother and murdered him after adopting his brother's son Agito. When Cronos secretly bought Max Pharmaceuticals, Genzo was appointed head of the Japan branch and produced many of Cronos' most effective Zoanoid models.
Makishima had been tasked with analyzing the Guyver units before they were stolen. He dispatched a Zoanoid squad to retrieve the units, but they were only able to recover one after an explosion scattered them. The other two would later be activated by Sho Fukamachi and Genzo's adopted son Agito (the latter of which Genzo would never discover). Following these mishaps, Makishima lost his position as head of Cronos Japan to Commander Richard Guyot, one of Cronos' leading managers.
As punishment for his failure to retrieve the Guyvers, Genzo was turned into a new prototype Zoanoid called Enzyme. While his optimization was incomplete by the time he was deployed against Guyver-1, his abilities were sufficiently effective and his desire for revenge against the Guyver drove him to success. Enzyme fought Sho Fukamachi and horribly mutilated him before pulling the control medal out of his brain. Without the control medal, the bio-boosted armour overloaded and began to devour Sho alive. As Enzyme and the Cronos agents left the scene of the battle, the Guyver's desecrated body got up again and tackled Enzyme. Deciding that Enzyme had fulfilled its purpose, Commander Guyot telepathically ordered Genzo to self-destruct. Enzyme's body exploded in a shower of gore and his corrosive blood melted what was left of the Guyver, leaving behind a disgusting heap of oozing meat which soon dissolved into nothing.
Zoanoid characteristics and capabilities
While Enzyme I was large and cumbersome, it possessed high endurance and could take a lot of punishment. When it fought Sho Fukamachi - Guyver I - it sustained a laser wound to the chest, a severed arm and even lost half its head, yet was still able to fight and win. Its main weapon against the Guyver was its blood, which possessed a potent enzyme that attacked the cells of the bio-boosted armour, swiftly dissolving it. Its blood would lose potency if it came into direct contact with the air and so Enzyme's body was optimized with numerous transfusers to transport its blood effectively. Its claws, teeth and tail barb could all pass on its blood through direct contact with the Guyver. Guyver I was unable to fight Enzyme at close range due to the creature's blood melting its armour and even lost one of its vibro-swords by slicing off Enzyme's arm.