For me, it kinda similar with north wall in game if throne. Kinda like 'make it calmer situation' or something. Things in the past are sure territorial right? Also it may also happened to be word choice thing bcs it didn't stated that those barbarians are the native in the novel so idk why it use the word native here.
If I remember correctly, the land beyond the dukedom should belong to those barbarians, thus making them natives to that place.
However, since those natives (aka barbarians) are harming the Villages that belongs to the dukedom, the Duke had no other choice but to drive out those natives from their home in order to prevent them from hurting the villagers. This is what they meant when they said "drive out the natives"
English is not my first language so when they said “drives out native” nothing comes to my mind (eventho I knew white people aka colonizer’s history)
Genuinely asking tho, maybe it was just the translations in this manhwa?? in the novel it’s translated as “barbarians”, is it still the same meaning?