Yan Ling's slash had cut the Hundun's stomach open.
Once her sword came out, there was a black liquid that suddenly came out of the cut that Yan Ling had made.
This black liquid splashed down onto Yan Ling, completely soaking her.
When I looked closely at the black liquid, I realized that the black liquid that came out of the Hundun was its blood.
After its stomach had been cut open like this, the Hundun still said, "No! How could this be! How could I lose!"
Once its stomach had been cut open like this, it wasn't able to maintain the flapping of its wings that was keeping it up. When the wings stopped flapping, the Hundun suddenly started to fall.
Yan Ling was right under the Hundun, so it seemed like she would be crushed to the ground by its heavy body.