After the Battle of Li City, Chu Mu, bathed in Jade Spring Holy Blood, had already shown a tendency to reach the Four Thoughts Soul Master level. He further progressed to the Four Thoughts Soul Master level on his journey from Dun City to World City.
Moreover, the effect of the Jade Spring Holy Blood does not seem to have completely subsided, prompting Chu Mu to take a few steps towards the Five Thoughts Soul Master level. Under the coercion of the White Nightmare Demon, Chu Mu finally reached the Five Thoughts Soul Master level!!
The elevation of Spirit means the strengthening of the soul. Once Chu Mu's soul becomes stronger, his own consciousness becomes the leader, gradually suppressing the soul of the White Nightmare Demon.
With the improvement of Chu Mu's Soul Sense, the pain of his soul burning gradually weakened. In fact, it was not that the temperature of the soul decreased, but that Chu Mu's ability to bear it became stronger.