The Undead Magic System, though a burgeoning school of practice, has already developed into three distinct veins:
Bone Vein, Corpse Vein, Soul Vein.
Cang Xu was an Undead Mage of the Soul Vein, characterized by the creation, containment, and manipulation of ghosts.
The specifics of controlling ghosts were akin to a demon energy ship assembling alchemy components.
The more components there were, the more functions the demon energy ship naturally had and the stronger it became.
However, there was a limit to this number. How many pre-installed slots the demon energy ship was designed to have, and how much demon energy the Mana Pool could supply, all significantly determined the type and quantity of alchemy components that could be loaded.
For Cang Xu, it was his spirit quality and mental strength.
A small flowerpot cannot grow a large tree.