To put it bluntly, everything that happened afterward can only be considered secondary reasons, but not the fundamental contradiction.
As for the rumors about Tianhe Venerable colluding with the Demon Sect or even going into madness, without this prerequisite, it probably wouldn't have had much impact.
Without these events, a conflict between Tianhe Venerable and the Four Sects would have been inevitable.
With the fall of Tianhe Venerable, the contradiction he had always suppressed with his strength was finally detonated.
Zheng Fa was even eighty percent sure that Lu Yao was the person behind it:
Although he didn't understand what was going on with that Lingxi Divine Monarch in the Turquoise Pool.
But the identity of Lu Yao as the Primordial Demon Ancestor was too suspicious.
It's just that he couldn't figure out the initial reason:
What caused Tianhe Venerable to attack mountains and break temples, and even eventually disappear?
...
