The terror of the Heavenly Demons lies in their ability to turn into thoughts and silently appear inside others' minds, which is the fundamental reason why the myriad tribes fear them.
If this were not feared, Heavenly Demons would not be viewed as so frightful in the eyes of the myriad tribes.
Those low-rank Heavenly Demons, formed by spiritual thoughts, if they do not reach the Demon King Realm and cannot achieve flesh and blood derivation, attacks such as fire, lightning, and sonic waves can cause great damage to them.
Some powerhouses can disperse and obliterate the spiritual thoughts of these low-rank Heavenly Demons with just a palm strike, making them extremely fragile.
The Yin Yang Separation at Dawn deployed by Yang Ji is a Primordial Spirit Killing Move, specifically aimed at annihilating spirits and thoughts like those of a Heavenly Demon, making it their nemesis.