Masaki Murakami is a friend and ally of Sho Fukamachi in Guyver: The Bioboosted Armor. He appears before Sho shortly after the destruction of Chronos Japan, offering to help in the continuing battle against Chronos. Later, Murakami reveals his prior connection to Chronos: he had been captured by Zoanoids after discovering them in New Guinea and the organization used him as a test subject for creating a new Zoalord. Murakami escaped from Chronos thanks to rogue Chronos scientist Prof. Yamamura, and while he now possessed powers far beyond normal humans, his lifespan had been reduced and calling upon his powers would shorten his life further each time.
In the twenty-third episode of the Guyver TV series - Ray of Annihilation - Murakami transforms one last time in order to protect Sho and friends from the attack of Richard Guyot. In the end, Murakami had his arm pulled off by Guyot, who then pulled the dummy zoacrystal out of his head, apparently killing him.
In the Guyver manga series, Murakami is ressurrected by Chronos's leader, Archanfel. His body is recovered from Relic's Point and is later re-optimized using the zoacrystal taken from Guyot. Murakami is completely brainwashed by Archanfel and takes Guyot's place on the Zoalord Council under the name "Imakarum Mirabilis".