Above the Heavens
"Finding the bone you're hiding in your chest was quite simple, you see? That one is mine. It's a bone taken from the left arm of my original body. The tribe that my original body belongs to is very special. Our body is tied to our soul. So, no matter where that bone stands, I only have to snap my fingers to summon it. As for controlling it, I am also the only one that can do that fully. The one that helped you organize this little theft must have been aware of that—which is why he left it with you," Huan Yi said and stood up.
The Demon Child was correct. Zi Xia could only use the bone to trigger wild and uncontrollable blasts of annihilation. By relying on one such blast, the half-demoness had even killed Saints! Alas, to say nothing of cultivating by relying on the bone, Zi Xia couldn't use its other powers and had to sacrifice one-fourth of her lifeforce for that one energy blast.