It happened. At the start, cavalry was built in the castle, and the external dwellings of pikemen, archers, and swordsmen were captured. All would have been fine, but I blundered again when trying to break through to the adjacent zone, and it turned out the reds were already operating there in full force. So I lost my entire army along with the scout hero. This time, I think I finally learned my lesson; hopefully I won't mess up like that again.
Thanks for the game.