Not all the Yang are dead, the sixth son's still alive.
4 seconds sound clip from the The Eight Diagram Pole Fighter movie soundboard.
You can hear this line at 00:16:42 in the Blu-ray version of the movie.
Quote context
[...]
- Our plan to destroy the Yang worked. They were annihilated at Jinsha.
- Why the delay? Why haven't you withdrawn yet so the Liao troops can replace you?
- I thought we had agreed to do that as well!
- My lord, I'm afraid our job's not yet finished.
- Not all the Yang are dead, the sixth son's still alive.
- Your Highness. Give me the opportunity to find him. There's not a moment to lose.
[...]