User blog comment:Endor 66/Why do Ruby and Yang have different last names/@comment-87.115.80.57-20140226171310

I have a theroy that is a bit complicated but it's the only one I can think of without thinking of them being adopted or step sisters. It is legal for a woman to keep her maiden name after marrige so my guess is that their mothers maiden name is Rose and their fathers name is Xiao Long. Because Ruby was born second she inherited her mothers last name.