"Chronicles of Troubled Times" records: There is a wonderful tree in the world, with blazing fruits. It bears one fruit a year, and each fruit shines in a place. An unofficial historian wrote: A noble tree rarely loses its leaves. Once the leaves do, it is said that the person who is destined to keep the tree is born. From the time when the leaves fall, all girls born within one day after that, when they are twenty years old, need to enter the sky realm and go through many layers of screening before selecting one person to find the path to the root of the tree and fulfill the responsibility of guarding the tree. Over the past thousands of years, the tree keepers have only changed twice.