Genzo Makishima is the head of Max Pharmaceuticals - actually the Japan branch of the Cronos Corporation - in the early chapters/episodes of the Guyver series. 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.
Enzyme, the Zoanoid that killed the Guyver
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 dessecrated 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.
This death occurs in both the Guyver OVA and the 2005 TV series.