"Black Xu"

[In the 1,257,917th year, the cultivation environment of the fallen Lost Land had, after Lin's improvements over these years, become even better than Qingming Hetong Heaven after its rebirth. Even your Qing Tong Residence was slightly inferior to where Lin cultivated. But this was not a place just anyone could enter. Its dense assortment of utterly evil qi was no good thing for ordinary cultivators.]

[Over these three hundred-odd years in the Lost Land, Lin and you had continuously calculated and finally gained a preliminary grasp of how to use "Black Xu." Of course, this was limited to using Black Xu once more. If it was handled poorly, even you and Lin might be killed by Black Xu along with everything else.

But this did not worry you. Your previous experiences had made you vaguely realize that the Black Xu created through black qi threads would form a certain balance with the golden cage made from Golden Qi Threads. This was not suppression, but rather a shared origin of some kind. Thus, wherever Golden Qi Threads existed, Black Xu's terror would be somewhat mitigated.

Now that you understood this, the direction for researching how to survive Black Xu afterward was beyond doubt. But condensing Golden Qi Threads was simply too difficult. Unless you were truly certain, you did not wish to casually use this thing for testing. Even you could not afford such extravagance; every small strand of Golden Qi Threads was enough to make you treasure it.]