The staged transformation is quite nonsensical, because essentially, it's a form of self-suppression, suppressing one's power and life form.
From the Chaos Plane to the Divine Light Alliance, Negris has only encountered a few creatures with staged transformations: the Dragon God, Demons, and the Gray Divine Star.
Ange's transformation isn't staged; it's simply changing his life form using powerful force, just a plain transformation.
The Dragon God lowers consumption, nurtures the Dragon Clan, and passes its power, experience, knowledge, and memory through bloodline inheritance, otherwise it couldn't survive in the plane; the consumption is too great.
It's essentially a survival strategy.
