With the advent of the two Royal Zodiac Battalions, dominated by their respective Royal Zodiac Generals, a majority of the Pandarens were subsequently redeployed to the Southern Walls since the Pandawans trusted the army to handle the situation in the North on their own.
The Pandawans felt that the Royal Zodiac soldiers would function better with their own troops and that random cultivators with no military discipline might just hinder them. This also gave the inexperienced Pandawans leading the rest of the cultivators to focus on one area, lessening their burden, since the South so far had only been able to use its advantage of elemental ammunition and equipment they could find within Demopolis.
