Fairy Peiyu had originally been a peerless genius disciple of the Moon-Deriving Sect, one seen only once in a century.
During the Demon Calamity several decades ago, she had been grievously wounded and left at death's door. A Native Heavenly Demon had corrupted her, turning her into a Mutated Heavenly Demon!
When the Heavenly Demon Passage opened once more, she had joined a wolf demon, an elderly demon, and a middle-aged demon—three great demons in all—along with vast numbers of low-order Heavenly Demons, appearing at Wolf Howl Ridge and establishing a Demon Cave in an attempt to unleash a horrific demonic tide.
Later, after Shen Mo, Golden Toad Pavilion Master Wei Ye, Doujin Sect Master Jiang Sheng, and the others fought bloody battle after bloody battle, they finally either slew or drove away these four great demons!
That Wolf Demon Heavenly Demon had been the king of the Fire-Spitting Wolf pack in Yue Province's Yuzhao Mountain Range. Shen Mo had slain it on the spot and refined it into a Demon Soul General. It had now entered the fourth order and was slaughtering and capturing the surviving Heavenly Demons within the Near-Sea Demon Cave.
Fairy Peiyu, the elderly demon, and the Middle-Aged Heavenly Demon, meanwhile, had fled this world and returned to the Heavenly Demon Realm.
Later, when Shen Mo had traveled as an envoy to Golden Turtle Island to negotiate an alliance with the Sea Clan, a hundred Third-Order Demons attacked. "Fairy Peiyu" and the Middle-Aged Heavenly Demon named Ghost Blade had been among them.
During that pursuit and escape, Heavenly Demon Ghost Blade, originally a disciple of the Nether Soul Sect, had also died beneath Shen Mo's sword, even contributing a Self-Sacrifice Immortal Art to him—the Wither-Extinguish Soul-Chasing Palm!
Then came the great upheaval of heaven and earth.