The setting of the Heavenly Demon World is somewhat modeled after the Void in the once-popular competitive game League of Legends, where an originally unconscious universe suddenly encountered some kind of terrifying energy fluctuation, ultimately causing the energy entities in this world to become restless.
Previously, the Heavenly Demons had no consciousness, but after suffering from a terrifying external energy fluctuation, they developed a defense mechanism, vowing to annihilate all threats.
Thus, the Heavenly Demons would frantically expand outward, which is the reason for continuous destruction.