Using

Madeleine thought for a bit, ignoring the pills before them for a moment. In the end, her eyes lit up with an answer.

"The Celestial Realm is the first step toward becoming a God. Not one in title, but a real, tried and true God."

Dyon's eyes flashed at this answer before falling into contemplation of his own.

What was special about the celestial realm? It was the moment most learned their Pseudo-Domains. To allow yourself absolute mastery over an area – albeit a small one – wasn't that an act of God?

At the same time, Celestial Energy itself was special. When one begins their cultivation journey, they spend the vast majority of the time dealing with essence energy. In fact, all three of the first realms dealt with essence energy solely. It wasn't until one became a saint that the form of energy changed, while entering the celestial realm gave way to another change.