Zaru can be secret agents of priesthoods striving for freedom, or they can collude with Ammeni masters to improve their own lot, perhaps for desperate and sympathetic reasons. They can also be passionate youngsters with no political aspirations, crushed by the limitations chattel slavery imposes on them.
Zaru can also escape their land to go elsewhere, but can they escape their past? An ordinary person might find peace elsewhere, but how about a hero?