(Second update!!!) Yuan Tian used a wisp of the Primordial Spirit within his Illusory-Extinguishing Star Eye to entangle the Phoenix Ancestor for a while, taking the chance to rescue the other Phoenix Ancestor.
While the Phoenix Ancestor was gravely wounded, Yuan Tian transferred the power of that wisp of Primordial Spirit to him, helping him heal. This suppressed the Phoenix Ancestor's injuries, but Yuan Tian's wisp of Primordial Spirit completely vanished as well. The result was that Yuan Tian, far away in Star Heaven thirty-six layers beyond, spat out a mouthful of blood and was injured.
The Primordial Spirit could be called the foundation of a cultivator. Some might say that a person's foundation should be the soul, and that was true as well. The soul was the foundation of one's existence; without a soul, one could not live. Even the Witch Clan, which had no Primordial Spirits, possessed souls—it was simply that their souls were fused with their fleshly bodies.
There was a premise attached to that: cultivators. The Primordial Spirit was exceedingly important to cultivators. The Witch Clan was an exception, since they did not cultivate.
When a Primordial Spirit was depleted, even completely depleted, it could still recover. Although the recovery of a Primordial Spirit was far slower than recovery from physical injuries, it could still be restored. But for someone like Yuan Tian, whose Primordial Spirit had been annihilated twice in succession, those two destroyed portions could not be recovered. He had to cultivate them anew. Cultivating a new Primordial Spirit was much slower than restoring one that had merely been depleted.
The sole benefit was that, due to Yuan Tian's cultivation technique, every time his Primordial Spirit was "wiped out," the Primordial Spirit he cultivated afterward would be far tougher than before—if that could even