The social ecology of Qi State is bizarre. Those in the Anxiang Clan who hold real power are called the upper class, while the merchant and artisan classes are referred to as the middle class, and the farmer class as the lower class.
This is the internal hierarchical system within the Anxiang Clan. Outside of the lower class, there are the ordinary citizens. In other words, even members of the lower class in the Anxiang Clan are still a step above the nameless commoners.
Additionally, soldiers belong to the lower class, but military officers are considered part of the middle class. And currently, the fastest path to promotion seems to be advancing from a soldier to an officer.
Thus, the Anxiang Clan is never short of provincial troops. They can continuously recruit strong young laborers from the populace to join the Nine Thousand Battalion and participate in the military actions of the Anxiang Clan.