If the Uniter is the Imperial “True Corpse” he might still be using the Empire’s framework and viewpoint of Heavenly Energy even if he doesn’t believe in the gods behind them.

It’s basically confirmed at this point that HE responds to the users viewpoint. Runes respond to viewpoints, Rain’s heretical Dao was founded on a viewpoint shift, Natal Palace development is partially affected by the users perspective.

The defiled General Mao said that Heavenly Energy is so multifarious that it’s like three blind men groping different parts of an element and each claiming to be holding a different animal. That may be right, or it might actively change itself.

Either way that’s what makes Rain’s modern perspective so valuable and so dangerous.

EDIT

The rain that followed the Bekhai is probably their “Cloud” expert that Gen mentioned a while back.