The Black Heaven Demon Patriarch was, after all, a supreme existence at the perfected Heavenly Immortal realm, one of the strongest beings alive.
Back then, he had suffered a backlash from his inner demon and fled in haste.
In truth, he had feared that White Moonlight, a Heavenly Demon, would fight like a cornered beast and deliver a desperate, fatal blow, taking him down with her.
Besides, the Immortal-Eating Gu's Source Gu and seven Golden Immortal-Eating Gu at the early Earth Immortal realm had been watching hungrily from the sidelines.
The Black Heaven Demon Patriarch had been unable to unleash his full strength while suppressing his inner demon, leaving him no choice but to retreat.
If he had completely suppressed his inner demon, or if it had possessed him, he would have been able to wield his full strength.
Without White Moonlight's help, the Python-Sparrow Heavenly Demon, the Gold-Devouring Insect King, and the Immortal-Eating Gu's Source Gu alone were no match for the Black Heaven Demon Patriarch.
Thus, even though Lin Fei knew where the Black Heaven Demon Patriarch's Secret Realm lay, he dared not go knocking on his door.
Before leaving Treasure Vase Mountain, he had even deliberately destroyed the teleportation array leading to the Black Heaven Demon Patriarch's Secret Realm.
After all, the teleportation array worked both ways. If he could reach the Black Heaven Demon Patriarch's Secret Realm, the Black Heaven Demon Patriarch could also use it to enter the Holy Demon Sect's publicly accessible Secret Realms.
This was a hidden danger that had to be rooted out completely.
Lin Fei worried that the Black Heaven Demon Patriarch might have left Primordial Spirit imprints or special tokens in certain Secret Realms.
Thus, every Secret Realm in the Devil Master's memories that the Black Heaven Demon Patriarch might