Initially, refining the Ancient Divine Power meant converting the divine power into a state of absolute perfection, like a droplet.
This allowed the divine power to stabilize.
Further refining involved attempting to infuse the divine power into oneself, emulating the divine body of the Ancient Gods, allowing the power to merge with oneself.
Beyond that, there was the Divine Heart that could generate divine power on its own.
However, the divine power contained the will of the Ancient Gods, which resisted refinement.
Generally speaking, if a Human Clan cultivator could preliminarily refine divine power, it was already quite impressive; refining a divine body might consume centuries, and it was even more challenging for the Demon Clan in the past.