Kai Shiden, an 18-year-old civilian on Side 7, enters the war with a cynical, sarcastic demeanor and self-serving instincts. Drafted into piloting the RX-77-2 Guncannon after a Zeon assault depletes the White Base’s crew, he openly resents military discipline, voicing constant complaints and contemplating desertion. His defiance softens only in moments of genuine crisis, when he grudgingly follows orders. During a stop in Belfast, his attempt to abandon duty leads him to Miharu Ratokie, a Zeon spy masquerading as a vendor. Learning of her struggle to support her siblings, he shelters her aboard the ship, forging a connection that reshapes his path. Miharu’s death—resulting from her unauthorized activation of the Gunperry’s missiles during a Zeon strike—shatters his apathy, galvanizing a transformation from cowardice to resolve. He destroys an MSM-03 Gogg at Jaburo and displays tactical ingenuity in pivotal battles like Solomon and A Baoa Qu, surviving the Guncannon’s destruction and engaging in close-quarters combat to defend the White Base. After the war, he abandons military life to study journalism at the University of Belfast, later becoming a freelance journalist and mediator. Leveraging contacts to aid groups like the AEUG and Karaba, he infiltrates Jaburo during the Gryps Conflict, covertly challenges Char Aznable’s leadership as Quattro Bajeena, and reveals Char’s identity to Hayato Kobayashi. He locates Miharu’s younger sister, Milly Ratokie, assuming guardianship while grappling with guilt over failing to protect her brother Jill from Titan forces. In later years, he collaborates with Kikka Kobayashi to document Amuro Ray’s legacy and partners with Bright Noa during the Laplace Incident, negotiating with Neo Zeon remnants to secure the RX-0 Unicorn Gundam. As a neutral intermediary, he brokers truces between the Earth Federation and anti-Zeon factions, using his journalistic reach to uncover covert agendas. The manga *Mobile Suit Gundam: The Origin* expands his backstory, depicting him as a delinquent held back a year on Side 7, initially clashing with classmate Amuro Ray. Wartime trials forge their camaraderie, culminating in Kai rescuing Amuro from Ramba Ral’s forces and improvising hybrid weapons like the “Cannon Zaku,” merging a Zaku II with a Guncannon’s head. His arc traces a journey from reluctant combatant to a behind-the-scenes strategist, driven by personal loss to mitigate conflict’s toll, balancing covert influence with a journalist’s pursuit of truth.