Board Thread:Speculation House/@comment-3257939-20131111020445/@comment-24130919-20131120041155

Maybe family names in the world of RWBY simply don't work the way we're used to. Maybe they're full sisters, who grew up in the same house with the same parents, and they simply have different last names because that's just how names work in their world.

Maybe the family name is only inherited by the oldest child. Or maybe the first child gets the dad's name, and the second child gets the mom's name. Or maybe family names don't normally exist, except for pseudo-nobility like the Schnees.