On the mood of the immortal descending to earth

The Journey to the West is the first romantic novel about ghosts and gods in ancient China. The mythical plot designed by the author is different from reality. In the novel, Buddha, Bodhisattva, immortal and demon are all characters in the story. They have magical power and can do things beyond human beings.

Being banished to the mortal world usually means that immortals or monsters are punished for their mistakes, reincarnated as human beings and lose their original magical powers. For example, the sand monk in the novel was banished to the underworld by the jade emperor because he broke the glass lamp, and became a tiger, suffering on earth.

So the meaning of this sentence is that the characters who made the most mistakes in Journey to the West were banished to the mortal world, lost their immortal identity and divine power, and suffered human suffering.