The eighth and ninth layers of tribulation clouds were quite different from the other layers. At the very least, after the first seven layers were pierced, cultivators' attacks could pass straight through the holes without being affected much by those layers of clouds—if at all.
But things changed starting with the eighth layer. Even after Ling Tian and the others pierced the ninth layer, the lightning gathered by the tribulation clouds could still greatly weaken attacks that passed through the hole. The lightning could even shatter those attacks outright. That was why Ling Tian's many earlier attacks had failed to pierce the ninth layer. Only after Po Di and the others widened the hole in the eighth layer, with Po Tian and Chi Xue's help, did they get the chance to pierce the ninth.
If the eighth layer was already like that, the ninth was worse still. In particular, only the clouds above Ling Tian and the others had been pierced; the clouds elsewhere remained intact. The lightning gathered by the ninth layer was therefore still extremely powerful. Even if Ling Tian's attacks passed through the hole in that layer, they would be greatly weakened, making it difficult to pierce the firmament.
Still, as Po Qiong had said, as Ling Tian, Chi Xue, Po Di, and the others continued their attacks, the hole in the ninth layer would grow larger and weaken it further. The impact on Ling Tian's attacks would then lessen considerably, and he would have a chance to pierce the firmament.
"Also, as more and more holes are punched through the eighth layer, other cultivators' attacks will have a chance to pass through them and strike the ninth layer. That will affect the ninth layer even more and further weaken its lightning, giving Ling Tian and the