True Immortal Five Tribulations, Heavenly Tribulation, Killing Calamity, See Me Calamity, Sentient Beings Calamity, Turbid Tribulation.
These five calamaties, as deduced by Tan Shuchang, were undoubtedly very powerful. Anyone below Heaven's Authority's Extreme would pale at their mention. And even for Heaven's Authority's Extreme, they would still be bound by these five calamities.
However, that was on the premise that in the Land of Netherworld, they recovered their original appearance, restoring the visions of the Immortal Path.
Just considering Tan Shuchang's secondary body in the "Minor Immortal Realm," even with the power of the Five Calamities and the assistance of those five fellow Daoists, it would still take at least ten thousand years to nurture.