To put it bluntly, the four snake demon sisters had essentially been tricked by the Daqian Sect, reducing them to demons kept in captivity by the sect.
It must be known that the predecessors of the Yanling Enchanting Snake clan had a most formidable background: they were none other than the Black Serpent clan from the Ruins Realm.
Although this lineage had since declined, the bloodline foundation of Lü Ling and her sisters still far surpassed that of ordinary rogue demons.
Chapter 383