There are altogether 29 bones in the skull. Generally, it could be divided into three parts.
6 ossicles, 8 cerebral cranium bones, and 15 facial bones.
The cerebral cranium bones are at the back, the facial bones in front.
Having already honed his ossicles, Fang Ping chose to hone his cerebral cranium bones this time. This was mainly because he felt that he could prevent getting snuck up upon from behind.
After honing the cerebral cranium bones, if he ever needed to make a hasty escape in the future while being hunted by others, the back of his head would have its own defense.
The size of the 8 cerebral cranium bones was on an entirely different scale to the ossicles.
The ossicles were the smallest bones in the human body. Judging from size alone, the bones behind the head were multiple times bigger.
Fang Ping guessed that the consumption would be much higher than honing the ossicles. He would not be surprised.