In the fourth layer of the Fire Prison, the surrounding temperature had risen by more than double compared to before.
However, Lu Ren cultivated the Golden Sun Law, while Wu Yuexi cultivated the Extreme Cold Law, so both could adapt to this environment.
The Fire Prison Immortal Beasts of the fourth layer were Fire Phoenix Birds. These birds were incredibly fast, skilled at flight, and exceedingly cunning, causing Lu Ren and Wu Yuexi no small amount of trouble.
However, Lu Ren's combat strength was too terrifying. He still easily broke through the encirclement of the Fire Phoenix Birds.
Yet the fourth layer of the Fire Prison covered a far greater area. Lu Ren searched for over a month before finding the Fire Phoenix Bird King. Man and beast fought for two hours before he finally slew it.
Afterward, Lu Ren entered the fifth layer of the Fire Prison.
The fifth layer was even more dangerous. The Fire Prison Immortal Beasts were no stronger than before, but their defenses and speed were far beyond anything previously seen.
Lu Ren spent more than two months before finally passing the fifth layer's trial.
Next came the sixth layer of the Fire Prison.
Inside were Fire Apes, each wielding a flaming staff. Their combat strength was ferocious, and when more than a dozen Fire Apes swarmed in to kill them, they gave Lu Ren and Wu Yuexi considerable trouble.
"Let's retreat first!"
Lu Ren leaped into the air, streaking across the sky and shaking off those Fire Apes before landing atop a mountain peak.
Wu Yuexi also landed beside Lu Ren and said, "Junior Brother, the Fire Apes in this sixth layer are far too strong. Sharpening the axe does not delay the cutting of firewood—we should make a breakthrough first!"
"That was exactly