In the current Four Great Secret Realms, it had become an arena for the Inheritors.
In the past, the Inheritors were still mysterious, their numbers were scarce. After ten thousand years, the figures of the Inheritors, while not exactly everywhere, lost the former sense of mystery and the intimidation they once held.
Some powerful beings even discovered that killing a Inheritor didn't seem to provoke retaliation. This emboldened them, and they were no longer as cautious as before. Of course, the precondition was that the difference in strength couldn't be too great.
A tier 6 Emperor going against a tier 4 Inheritor was unacceptable.
If it went unnoticed, it might be fine, but if discovered, the Qishen Temple would blacklist the Emperor, and a warrant would be issued.
Of course, this was the case in the Heavenly Realm; the same treatment didn't apply in the Earthly Realm.