Caitou Kai's shed shell still retained Legendary Grade combat power.
But because it had been suppressed in the Black Prison for too long, its vitality had been severely depleted. On top of that, Caitou Kai had withdrawn its primary consciousness, leaving the shell with only combat instincts and little intelligence. How much of that power remained was highly debatable.
It should not originally have been a match for Professor Yao.
However, before fleeing, Caitou Kai had applied a berserk enhancement akin to "Demonic Dismemberment" to the shell, forcibly boosting its combat capabilities. Meanwhile, Professor Yao not only had to use his true body to suppress Caitou Kai's shell, but also divide his attention to deal with demons taking the opportunity to "bore holes" elsewhere in the crystal wall, while avoiding striking too hard and damaging the Black Prison World himself.
Even if he truly had three heads and eight arms, he could not fully wield all his abilities while focusing on so many things at once.
He had to fight with his hands tied.
Seeing Zheng Qing arrive to help, he was naturally delighted.
He knew Zheng Qing's background well. He knew the other three Legends followed Zheng Qing's lead, and that Zheng Qing carried immense karmic ties, with every action affecting many things. He had originally intended for this Dean Bian Yuan to remain at the edge of the battlefield, safely hold Black Prison Castle, and clean up the troublemakers within the world. Then he would personally deal with the shell Caitou Kai had left behind with all his strength.
Yet in a moment of inattention, he had allowed that shell to retreat back into the world.
The Black Prison World was vast and boundless. Aside from the prisoners held in Black Prison Castle, wizards generally let the others