"Annoying."
The more Li Yunmu thought about it, the more confused he became.
Muscle Marrow Body Refining Secrets could transform his innate talent and body structure and boost his comprehensive ability. Due to this, it was extremely important to him.
This was especially so now when he was trying to break through to rainbow crystal layer and needed a large amount of active rainbow crystals. It was usually very difficult to encounter even one rainbow crystal dimensional beast, so where would he be able to find them in great numbers? Heavens only knew how long it would take him.
The improvement in his comprehensive ability was also an important factor here. The increase in proficiency completely depended upon the person's perceptiveness. If their comprehension was high, then they could easily become proficient with battle skills, but if their comprehension was low, then it would take them twice the effort.