I don't really get the whole slave aspect to this it makes no sense. a slave tribe that is powerful enough to be sought as bodyguards for heads of state but still seem to willingly enslave themselves while not being treated as slaves? they legit seem to have self governance with a chief and all that
they legit slaves in name only so that they can make the mc out as the underdog.
just make it some warrior village that specializes in exporting bodyguard services and the like and it makes much more sense