What is Power Primordial?
The Power Primordial is residual energy left over from the Big Bang that created the current universe. The circumstances in which the various Elders each gained some of this energy are yet to be revealed. While the energy itself is vast, it takes years of intensive training to purposely channel the energy to grant each of the Elders the various superhuman physical, mental, or energy manipulative capabilities that they possess. Each Elder has purposely channeled the Power Primordial to grant them greater abilities in some areas than in others. This renders the Power Primordial similar to the cosmic energy housed in the bodies of the Eternals.
The Elders of the Universe refer to the power they possess as the Power Primordial. It seems to be the use of cosmic energy similar to the Power Cosmic.