The Soulless sleeping in the shadowy realm had been awakened.
They were the inhabitants and masonry of the shadowy realm and dreamland. Before the disturbance, they were fused together with the world. They were the stone carvings and murals, the twisted faces on dead trees, weird stones in the corners, and the shadows of overlapping clouds. They were all hidden in various corners of the world. When the intruders came in, they all "woke up" and emerged everywhere.
As Hao Ren and the rest retreated, they shattered many phantoms on the way. They finally found their way into a tall and sturdy castle. As they shut the heavy oak door behind them, the never-ending shrills in the courtyard finally calmed down, becoming soft like a breeze.