In this chapter, we learn that valuable artifacts are divided into four grades: mortal, treasure, law, and king. It is said that the higher the grade, the stronger the item. In other words, if you have a treasure grade item, you're going to have a harder time refining pills than someone with a higher grade item. This is because refining pills is a progressive process, and refining pills with a lower grade item is like refining water with a black spirit cauldron. The price of this cauldron is a hundred spirit stones, but if it were someone else buying it, it'd be even higher. So, if he can buy this cauldron on credit, he'll be able to pay it off in one fell swoop.