The process of refining the Ten Thousand Spirit Elixir is essentially a process of repairing Fang Xing's Dao foundation.
Since Fang Xing ventured into the Ten Ceremonial Arrays ten years ago and shattered his Dao foundation, his Dao source has been leaking, until it was completely drained and hasn't recovered to this day. Even though he can now wield mana, this mana is actually borrowed from the Ten Thousand Spirit Elixir, and not his own cultivation. Simply put, his cultivation has not been restored; his Dao source within remains depleted, almost entirely lost. Without the Dao source, mana cannot be retained, leaving his body empty and making him a cripple.
Now, he can use spells and even fiercely battle Nascent Souls, all relying on that clump of Ten Thousand Spirit Elixir.
The Ten Thousand Spirit Elixir is essentially a clump of Dao source containing powerful mana, which Fang Xing's mana and even life force are borrowed from.
