What is the name of the novel of the Great Devil told by Qian Er on 20 16?

All the immortals in heaven came to earth. Four days later, the king came, Chang 'e came, Lv Dongbin came, the seven fairies came, and there were terrible monsters.

The novel tells the story of Xiao Qiang, a celestial agent who was forced to take office, inexplicably involved in the celestial war and led a group of immortals to save the world.