If a mortal said something rebellious, or did something that could possibly affect the balance of the world, the Eye of Heavenly Dao would appear as a warning or even directly kill the offender.
Eye of Heavenly Dao was the guardian of the balance of this world, and was also able to command the power of an entire realm.
It guarded the order, and could directly make use of the rules of this realm so that no one would be able to transcend the rules.