No external means can harm the Flawless Heavenly Dao.
In this mode, even if It wished to damage itself, It wouldn't be able to!
Unable to be harmed, unable to be expelled, unable to be sealed, unable to be cursed... every method you can think of is meaningless to the 'Flawless Heavenly Dao.'
Some humanoid Heavenly Daos can't even 'cut their own hair.'
So, even though Tyrannical Song's 'Heavenly Dao Pillar' made the Fourth Dark Heavenly Dao feel inconceivable;
Even though Tyrannical Song kept pulling out 'Heavenly Dao Pillars of past eras,' causing the Dark Heavenly Dao to be greatly shocked;
The Fourth Dark Heavenly Dao didn't panic in the face of Tyrannical Song's targeted assault.
It remained extremely calm, its mind and willpower still wholly focused on the 'Heavenly Dao Authority Struggle' with Tyrannical Song—aiming to take him down using its Heavenly Dao Authority Operation experiences, which were a million times richer than Tyrannical Song's.