It's important to remember that they were cultivators.
By the time they reached the Golden Core stage, they rarely felt the cold or heat.
The ice and snow of winter and the blazing sun of summer couldn't penetrate their spiritual energy defenses.
"The temperature is rising more and more. What's going on?" Another disciple wiped the sweat from his forehead, watching it drip down the side of his face.
"Renshu Chang, what's going on? Why did the temperature in the cave suddenly get so high?" Senior Brother Cao asked as he approached Renshu Chang while wiping the sweat from his brow.
The other disciples, who had slightly lower cultivation levels, were already sweating like they had just been pulled out of water.
Renshu Chang, with his higher cultivation level, was the least affected among them, but even so, he still felt the intense heat.
If he was struggling, the others were surely having a harder time than him.