The Rat Tribe had originally been one of the great races of the Demon Race. Before humanity rose to prominence, the Demon Race occupied Shenzhou, and the Southern Wastes were the Rat Tribe's stronghold.
Later, when the war between humans and demons broke out, the Demon Race withdrew from Shenzhou and fled into the Southern Wastes, where they encountered fierce resistance from the Rat Tribe. Thus, during the "Three Sacred Wars" in human history, a great war between the Demon Race and the Rat Tribe also erupted in the Southern Wastes.
The human war ended with the Confucian Sect establishing itself in the world, the Daoist Sect retreating into seclusion, and the Buddhist Sect journeying west. Likewise, upon the lands of the Southern Wastes, the Rat Tribe was thoroughly exterminated by the united Demon Races.
This extermination meant that, from the Ancestor Demons downward, every member of the Rat Tribe—including all its Great Sage bloodlines—was completely wiped out.
From then on, the Source of Bloodline of the Rat Tribe dried up, and the tribe's glory vanished like smoke in thin air.
The once-prosperous race had disappeared without a trace.
Returning to the present, during the case involving the murder of the newly crowned top scholar Tang Anshi, Chen Luo had gone to Qing'an Prefecture to investigate. While searching for Tang Anshi's teacher, Magistrate Min, he encountered the Qing'an Rat Tribe, who had become demons, and learned from them what had happened to their people afterward.
After the Source of Bloodline dried up, members of the Rat Tribe occasionally still became demons, but at most they were seventh- or eighth-grade Blood Realm demons.
That continued until Chen Luo wrote Legend of the Eight Immortals!
Among the stories in Eight Immortals was one in which Zhang Guolao sacrificed himself in the form