"Marmot" is a derogatory name given to a man who appears in the first episode of both the 1989 Guyver series and the 2005 Guyver anime. He is an incomplete prototype Zoanoid, a human that has been genetically altered to serve as a biological weapon.
Next to nothing is known about Marmot, only that he escaped from the Japan branch of the Chronos Corporation, a secret society researching into alien genetics and bio-weapons. During his escape, he stole the three Guyver units: bio-mechanical devices of alien origin that contained limitless destructive potential. Marmot intended to trade the Guyver units to a traitor within Chronos in exchange for having his Zoanoid optimization reversed. However, he was pursued by Chronos agents who cornered him in the Mount Narisawa region. Marmot fought against one of Chronos's Zoanoids - a Gregole - but was not strong enough and had his hands crushed. In order to prevent Chronos from retrieving the G-units, he activated a bomb and blew himself up. The explosion scattered the Guyver units across the woodlands and Chronos were only able to recover one of them. The other two would later be activated by high school students Sho Fukamachi and Agito Makishima.
Even if Marmot had not blown himself up, he would soon die regardless. His Zoanoid adjustments had not been completed at the time of his escape, thereby reducing his lifespan to a mere seven days.