The qi became purer as the color of it changed from a lighter shade to a darker shade. This improvement might seem minor but collectively it is a sight to behold.
He could now feel the benefit of cultivating the Chaos Body Forging Technique, if he hadn't cultivated that technique then his body would have collapsed from the enormous pressure that was put on it by the Primordial Vessel Cultivation Art.
A normal cultivator could have never cultivated this art even if someone gave it to them, it was nothing but a death sentence.
Shen Yuan's body trembled lightly due to the pain and refinement of his Qi. His body, which already underwent extreme pressure and pain due to previous refinement and Acupoints opening, was adapting to this new strain, forging itself anew as his bloodline also helped with sending a wave of energy towards his direction.