For all kinds of machinery used by civilians that required firepower, a letter of guarantee from a scholar or a government official in charge of the local regions and the likes must accompany it. Meanwhile, the highly respectable individuals within their area could purchase Ziliujin a grade lower at the stores of the Imperial Court.

However, Ziliujin was immensely profitable; it could not be stopped even after repeatedly banning black markets. There was a saying - 'birds doomed by food, humans doomed by wealth'. The number of desperate people who were willing to exchange their lives to earn money had been numerous since ancient times. But even if they were willing, if there were no sources to provide, it was still useless.

The earliest black market's 'gold merchants' all went to the grassland to try their luck. But not even one in a thousand of these people had a single stroke of luck, most of them already died halfway.

The Heavenly Wolf sect aimed for Great Liang's black markets - they did not hesitate to kill the chicken to take the eggs. Every year, a large amount of Ziliujin was dug up. After paying their tributes, the extra Ziliujin was used to bribe the soldiers and officers in the border areas, bringing them down one by one. This was the 'Gold Erosion' plan.

This plan was slowly entered into action about seven or eight years ago. Later, the barbarians had gotten in touch with Hu Ge Er, who was living at the time in the small town of Yanhui. The two sides assisted one another. After many years of paving the way, the barbarian prince was quite confident: in this crucial town of the Northern Frontier, there was not a single corner where his hand could not reach and his eyes could not see.

But if only Heaven and Earth knew of this, as well as the culprit himself, how could Gu Yun have known?

Did he really possess eyes that could oversee everything?

In just a span of only a few sentences, the fight for the Giant Kite in the air had been settled with no delay.

The wicked Gu Yun, with both hands behind his back, was still not satisfied and proceeded to stab at them one more time:

"Your Highness, I'll tell you the truth, this Gu has been waiting for you for a long time in this godforsaken place, having nightmares about you not coming every single day – If you didn't come, what excuse would I use to clean up these insects eating up royal wages and doing nothing? Truly, thank you!"

The barbarian prince looked as if he wanted to tear him into pieces. Gu Yun saw that he had almost turned mad from anger, the irritation from his powerlessness of being unable to deal with Chang Geng just now finally subsided, and he revealed a smile.

"Gold Erosion, haha, truly brilliant - no more talking nonsense: capture them!"