What does the end of the soul ferry mean?

After analysis, the whole story should be like this: After nine days' descent, an accident happened to the immortal Xuan Nv, which separated her Yin and Yang, and the Yang soul was reincarnated as the king and the ghost reincarnated as her sister. Ghosts belong to yin, and you can see ghosts in the underworld, which is also a great supplement to ghosts. The ghost chased her and killed Xia Dongqing's sister. The ghost was rescued from the body by Zhao. ...