The warriors would travel in tunnels constructed between underground caves, riding flying boats powered by the curse.
Hero is a redesign of the 2002 Wuxia film "Hero" with a fantastical twist. The symbolism of colors from the original is also extended into the new locations.
The empire of Qin (200 BC) was cornered in a curse cast by alchemists from neighboring nations. As the war went on, the army of Qin would make use of the curse as an energy source for weapons and technologies.