Cheng Qing's expression was extremely grave. He naturally knew the severity of this matter.
He had been the one to deal with the black energy that had burst out of the Black Mountains several times before. Each time, the scale of the black energy was extremely small. At most, it had only devoured an entire batch of prisoners and supervisors.
However this time, the black energy had devoured all the living beings in the Heavenly Region!
From this alone, one could see how serious the situation was.
Thinking of this, he reminded Jian Wushuang, "Brother Jian, the black energy can easily be contaminated by Yan power. Once it's contaminated, it's difficult to get rid of it. So, when we reach the place later, try not to use Yan power if you can."
Jian Wushuang nodded slightly and looked through the void at the Heavenly Region that was emitting dark energy.