A couple generations back, my great great grandparents moved to a new country and just… picked a new surname. It was a popular local surname. That made it easier to render in the local languages, easier for folks to pronounce, and it sounded familiar to them so it helped build trust. It doesn’t even sound similar or mean something similar to the previous family name, it was essentially random.
Whenever a kid is born into the family they’re given two full names. An everyday name (with that new surname) and a separate name that includes the old family name, so there’s still that cultural link. The outward-facing name is still the one we use most often, but everyone switches to the private names when they switch to the old language. I wasn’t even raised bilingual, but I know my other name.
I like to imagine that’s what happened with the faction surnames. Maybe Rook also has a “real” family name that they privately know (or no family name at all, depending on the culture they’re from), but most of the time they use the updated one.
That can be played both ways. Maybe they don’t strongly associate names with their heritage, so why not use one that makes things easier? On the flip side, maybe they’re extra proud of their private name and think “outsiders don’t get to know my real name.”
