The purification of chemicals always faces the greatest challenge in removing the last bit of impurity, and expelling the cold energy from Elder Feng's body was no different.
The remnant of the cold energy had truly seeped into Elder Feng's bone marrow; removing it without harming the old man's body required extreme caution and was actually more difficult than the previous attempt, testing Ge Dongxu's control over True Qi. If Ge Dongxu were still at the Qi Cultivation Fifth Layer, he would have ended up exhausted just like last time, treading on thin ice with the utmost care.
But this time, Ge Dongxu had reached the Sixth Layer of Qi Cultivation, which made the expulsion of the cold somewhat easier.