The Yin Spirit Ghost Flame was special, as only soul-formed beings could absorb it. This cold flame had the energy power that could control the spirits or wandering ghosts of the Underworld. At the same time, it contained the martial path of the Underworld’s Sage.
Apparently, a creature of the Underworld had occupied this flame. However, he didn’t have a body anymore. That was how his soul could merge with the Yin Spirit Ghost Flame.
He needed to create a new body to promote his supernatural powers.
To create a body, it normally required the strong flesh and blood to be refined by the scorching heaven flame. If he could have another heaven flame, he soul would be mightier, and the chance of having a body could be bigger.