Wang Wei proceeded to absorb the [Secret Spirit] since he understood it well. He was in tune with his emotions and had a great understanding of the interaction and attraction that drove people–especially himself.
Because he understood these aspects of the souls, he could fuse the [Secret Spirit] with the Primordial Spirit. The Three Immortal Stage is the cultivation stage where a cultivator's comprehension is more important than their body.
Without understanding the different aspects of the Three Immortal Stages, it is impossible to combine them with the Primordial Spirit and enter a stage of completion.
After fusing with the [Secret Spirit], Wang Wei felt that some missing part of him had returned. He felt complete and fulfilled; at least, he was in the process.
Additionally, he discovered that he lighted up more than 50 billion new spirit particles by completing the Primordial Spirit. The power of his soul increased drastically.
