The ghostly soul of the noble family child is nearly indestructible; it's common knowledge, which is why Su Houzhang had confidently devised a plan to "stick with the evil spirit."
However, this "common knowledge" shattered in Song Cheng's hands.
The ghostly soul of that mysterious monk was directly crushed by him.
In this process, Song Cheng also gained a deeper understanding of the "Reappear," a unique power of the evil spirit.
Reappear, actually akin to "imprisonment," "Soul Arrest," is about pulling your divine soul instantaneously into the "Reappear World," after which you can never leave.
And in the "Reappear World," the strength of your physical body, the power of your soul, are all ineffective, for Reappear is a very terrifying type of "imprisonment."
But "Reappear" is just imprisonment, not destruction, so many who were killed by evil spirits still had their souls undestroyed, merely temporarily existing in the Reappear World.
