Forming a core was the last step that Max had to complete to become a celestial.
A core was like an additional organ which helped god's process karmic essence and become a true celestial.
To form a core, one needed to separate their soul into three smaller portions in the ratio of 90-5-5.
90% of the liquid soul essence one had was condensed to form their soul core.
5% of their soul essence was cut loose and it floated freely in the universe accumulating karmic essence and solidifying into a seed of power.
The nature of the seed of power created depended on the strength of the ascending soul and the nature of the soul, but there was never a guarantee on output.
Finally 5% of the soul was transplanted into another body, transforming them into a soulmancer.
As long as even one of these three entities remained, a celestial could never die and their dissipated soul essence would always reform over a period of time.
