To achieve the status of a first-class Heavenly Immortal, the demand for the spiritual energy of heaven and earth is immense. Even draining the spiritual energy of hundreds of great worlds in an instant might not suffice, and assistance from a Chaos Immortal is required to cultivate a first-class Golden Elixir.

At this moment, Xu Zong uses Chaos Spirit Liquid as the energy source for the evolution of his inner world, ensuring that there is no lack of energy. However, a first-class Golden Elixir requires more than just energy.

Over the three hundred years depicted in the "Bright Moon Landscape Scroll," Xu Zong has also deduced the Heavenly Immortal volume of the "Inner Observation of the Free Heaven and Earth Sutra." He believes that to cultivate a first-class Golden Elixir, not only is immense energy required, but also a profound understanding of the Dao.

Specifically, this means at least comprehending the relative attributes of the Heavenly Dao, which is extremely rare even among Ancestor Immortals. Generally, only Chaos Immortals can achieve this, which is why their assistance is necessary.