"If you want the Prehistoric World to possess Eternal Attributes ahead of time, you cannot use these Half-step Eternal powers to nourish Heaven and Earth, but should instead gather them together to evolve the Eternal Realm."
The clever method Jiang Chen thought of is related to the power at the Half-step Great Dao level that was swallowed by the Chaos Green Lotus.
Over thousands of years, the Half-step Eternal level power left in between Heaven and Earth after the Chaos Demigod self-destructed has mostly been absorbed by the Chaos Green Lotus.
But these powers, although swallowed by the Chaos Green Lotus, were not used to enlarge the Prehistoric World but were intercepted by Jiang Chen.
He wants to take this power that involves the mysteriousness of eternity to explore the Eternal World.