In his past life, Chu Xuan, the Supreme Demon Lord of Nine Heavens, was besieged by the Twelve Holy Demon-Slaying Sects of the Human Race. His Dharma Body self-destructed, and his Divine Soul unexpectedly reborn as a green caterpillar no more than half an inch long. Trapped in a desperate situation, he awakens the Devouring All Beings System, gaining power by devouring everything. From the bottom of the grass thickets, he fights and devours poisonous insects and spiders, consumes the remaining bones of demon beasts to complete his first transformation, becomes a young serpent, and sneaks into the Black Wind Demon Sect as a snake servant to hide and grow stronger. He advances cautiously, devouring powerful enemies one after another, undergoes multiple form transitions — snake, python, anaconda, flood dragon — rising all the way to become a True Dragon of Great Vehicle.