Since the establishment of the infinite purgatory, the weakest of those confined within were at the realm of the ancient Daluos, and even Quasi-Saints weren't exempt from finding themselves imprisoned there.
The heads of all parties must be insane to dare offend the Underworld authority. Should they truly enrage the Underworld judges, and end up locked in the infinite purgatory, only the intercession of a Saint could ever hope to save them—otherwise, escape would be a futile wish.
Recently, due to the demise of the Emperor of Fengdu, the Underworld authority became much more subdued, but even a camel on the brink of death is still larger than a horse. Within the Three Realms, there are still very few who would dare to offend the Underworld authority.