The Immemorial Celestial Body was from the Ancient Clan!
The Ancient Clan was one of the Four Big Holy Tribes in the Absolute Beginning Divine World, powerful in both close combat and preservation techniques.
The Immemorial Celestial Body was the Ancient Clan's trump card.
When comparing the Immemorial Celestial Body and the Body of Eternity, most would likely agree that the Immemorial Celestial Body was slightly stronger, for it increased the strength of the holy body as well as one's own Divine Power. The only flaw was that it could only be cultivated by someone that possessed the Bloodline of Ancient Clan - the Ancient Clan.
Therefore, although the secret skill was powerful, it was not very popular in the Absolute Beginning Divine World.
Because even if Absolute Beginning Divine World cultivators were to obtain the secret skill, they could not learn it.
