The Yin Spirit Bigwig knew quite a bit about the Jinwu Nirvana Technique. It said the emphasis of this technique lies in the word Nirvana. Whenever one is about to cross a boundary, they use Nirvana to charge through. Afterward, their cultivation level resets to zero, and the person reverts to infancy, then quickly recovers.
In other words, at the third, sixth, and ninth levels of the Out of Dust stage, one must undergo Nirvana to successfully break through.
According to the Bigwig's analysis, Sun Rongxun encountered problems with Nirvana at either the sixth or ninth level of the Out of Dust stage, thus failing to fully recover.
What should be done to treat this situation is not entirely clear to the Bigwig, but it understands that the reason Sun Rongxun's vitality is so abundant is due to the interruption in the Nirvana process, which allowed for some vitality to accumulate.
