Ch543: The main battlefield
Nothing much from what I can get from the spoilers. Seems like a flashback chapter with Ousen sending Shin to assist Ouhon. According to Ousen, a victory at the right battlefield would mean a total victory for Ousen. Chapter ends with Shin leading the entire 8000-men HSU into battle.
Edit: Full chapter in Korean: https://imgur.com/a/qxc30