Chey used his expertise in explosives to destroy countless villages during the Hundred Year War. However, after seeing many innocent people's lives ruined by his actions, Chey began to question the War's purpose and his role in it. Three years before the re-emergence of AvatarAang, he became the second person to desert the Fire Nation Army and survive. Upon learning of Jeong Jeong, Chey searched for him, hoping to gain some of his spiritual knowledge. Chey had been a part of Jeong Jeong's tribe for the next couple of years, attempting to learn all he could from the great master, and gain enlightenment himself.
When Aang and his friends attended a Fire Nation festival, the colonial village discovered Aang's true identity, and the three friends quickly attempted to escape from Fire Nation soldiers. Fortunately, their escape was aided by Chey. As they flew away on Appa, Chey explained that he served the firebending master Jeong Jeong who had abandoned the Fire Nation. Chey led the group to camp within a forest, but they were intercepted by Jeong Jeong's followers.
They were led to the camp, where Aang attempted to learn firebending from Jeong Jeong. After Admiral Zhao and his troops attacked the site, it was abandoned. Chey had been in the forest, knowing nothing of what had transpired, and returned to the campsite only to find it deserted.
When Xin Fu and Master Yu visited the Misty Palms Oasis months later, there was a Fire Nation wanted poster of Chey placed on the local information kiosk; he was still eluding the Fire Nation by the time Aang had begun learning earthbending.