Despite the war and various responsibilities as Emperor, Lind never stopped looking ahead. His unique issue of harmony aside, the step between Moon Tier and Sun Tier was close to the gap between World Realm to Sky Realm.
For normal cultivators, it was a fusion of their relatively new secondary elements with their primary elements. It was a process to make the disparate parts become whole. The process naturally transformed the moon into a sun.
The furnace would churn as the elements kept flowing into the sun to feed it and make it grow. The elements would continue to fuse inside it as well until what was just barely balanced in the Star and Moon Tiers becomes truly balanced.
It was why becoming an Immortal Realm was so difficult. The Sun Tier was the make or break point for cultivators.
Even if one could make it into that tier, the fusion process may never reach the critical stage of being complete so they could face their Immortal Tribulation.
