Based on Lin Qiye's words, not only did he know that City Lord Wang had already escaped, but he also knew the demons were much more than they had previously estimated.
No one on their side had told him about the situation. In that case, the only explanation was he had found out all the information himself.
As Immortal Realm powerhouses, everyone knew very well that some existences with strong enough mental power could easily see all the movements within a radius of thousands of miles when they spread their divine sense.
For example, as an expert at the peak of the Earth Immortal Realm, City Lord Wang's mental power was also decent.
With a spread of his divine sense, he could explore the situation within a radius of two thousand miles.
Lin Qiye's strength seemed stronger than City Lord Wang's, so it made sense that he had used his divine sense to investigate things they did not know about.