This point alone was enough that Lin Xuan did not dare take things lightly.
After all, even Tribulation Transcendence existences were wary of the legendary Heavenly Demons. Merely sending out a few incarnations was not enough; Star-Moon City had the true body of a Tribulation Transcendence mighty expert stationed there all year round.
Later, after Lin Xuan returned, he had also looked through some ancient texts on and off.
And in some lone surviving copies passed down from antiquity, he had discovered a few vague, fragmentary descriptions.
Yet as for what Heavenly Demons actually were, it remained a foggy muddle, and he had never fully figured it out.
What could be confirmed, however, was that Heavenly Demons were not Ancient Demons. Of course, they were even less existences of the Spirit World or the Underworld Realm. It could even be said that they came entirely from another plane, their habits utterly different from the beings of the Three Realms.
Lin Xuan had once seen a conjecture in an ancient text.
It said the place where Heavenly Demons lived was vastly different from the Three Realms, but these demons were all incomparably powerful, and most of them had no fixed form or body.
Some were even nothing more than a single demonic thought.
Even in the bizarre and motley world of immortal cultivation, such existences could be called inconceivable.
However, having no body was one thing, but the strength of Heavenly Demons was beyond doubt. Legend even had it that the most powerful existences of that race were called Outer-Domain Heavenly Demons, and their strength could rival that of True Immortals after Tribulation Transcendence and ascension.
Fortunately, although Heavenly Demons were terrifying, under normal circumstances, it was also very difficult for them to have any intersection with the Spirit World. It