A Heavenly Emperor was like a heavyweight bombshell or a nuclear bomb, being a deterrent.
The destructive force of a Heavenly Emperor was too strong. Secular cities were not much different from toys to a Heavenly Emperor.
Furthermore, the survivability of a Heavenly Emperor was extremely strong. They were exceedingly difficult to kill.
Once a Heavenly Emperor was determined to seek vengeance, even if he was only a First Firmament Heavenly Emperor, his destructive power would also be extremely astonishing.
Hence, there was this unspoken agreement between heavenly emperors to not intervene in worldly affairs.
Once the Heavenspan World becomes depraved, then the Heavenspan World would wail in sorrow.
Now, Heavenly Eagle Imperial City produced a Heavenly Emperor. They had sufficient capital to play with other Heavenly Emperors.
They could take a share of the loot from the Southern Border, this large cake!