Judging from the plot, Jiumei should be 20 years old. How can she have the ability for hundreds of years? And how her father called him his second daughter and second sister.

Well, think about it, their father has already confessed that it will be a once-in-a-lifetime event, and now he is 999 years old. Do you think his daughter can be several hundred years old? You can't tell their age from their appearance. Besides, it is normal for Jiumei and the demon emperors of past dynasties to ask those beads to save lives and pass on some skills. As for the second sister, is it because the second child is already very big in nine? If you have to say a reason, then omit the word "she". The protagonist of the whole play is Jiumei, or Jiumei's second sister. Then I used to be called second sister, which is a light comedy of father-daughter relationship. Don't think too much. Please adopt if you like.