"Building Upon Building" may sound like the name of a restaurant, but it's a name feared by many in Danliang Country, and even across Chengshui Country and the Turkic Tribes. That's because it's a cryptic underground organization whose mission is to abstain from royal affairs, and not to be used by any country.
It was said that "Building Upon Building" once targeted a high-ranking general. In less than three days, the man's head was hung at the top of the military's flagpole. Not a single soldier knew what had happened, let alone caught a glimpse of the murderer's shadow.
Another tale had it that "Building Upon Building" once needed a treasure that was in the imperial palace of Chengshui Country. The emperor of Chengshui didn't believe in their prowess and arranged heavily-armed guards. Resultantly, within less than three days, the treasure disappeared without a trace, as if taken by unseen forces.