Back Mountain, Cave.
Although Lu Xun had already left the seclusion, this cave temporarily became his artifact refining place.
The life occupation settings of "Heavenly Dust" are quite fragmented, like artifact refining, it doesn't directly give you a refining level to upgrade; then you can refine freely.
For example, if you want to refine a paper crane, you would need to spend experience points to learn the refining technique of a paper crane.
The production method of each magical weapon, requires experience points to learn.
However, after learning, there is an experience reward for each successful refining, although it's not much.
The paper crane is a superior yellow level magical weapon. Although it appears to be not high in rank, it's already quite luxurious among flying magical treasures.
Because besides being able to fly, it serves no other purpose.