Quinn is an enigmatic figure - a sort of hybrid between human and alien. Sometime during the 1953 invasion, the Supreme Commander of the Mor-Taxan army possessed a man, but due to a biological fluke Quinn discovered that he was immune to the same bacteria that befell his comrades. However, he also found himself trapped in the human body. Quinn found himself alone on the planet he was sent to conquer, with a strong advantage, but with no military to aide him.
Quinn made the best of it for thirty-five years, surviving as a brilliant and reclusive artist, but now that the Advocacy is awake again they're hunting him down for his organs. He has other plans, and kidnaps Harrison to try to achieve those goals. He wants to deliver victory to the army of three million Mor-Taxian colonists on the way. His strategy, offer the UN the opportunity to save 10% of the human race on reservations by surrendering to him, rather than the extermination they'd face under the Advocacy. Aliens track the pair of them to the UN, though, and Harrison manages to save him with some makeshift pyrotechnics. That and Blackwood's arguments that the aliens would never accept him convince Quinn to let Harrison go.