Board Thread:Speculation House/@comment-3257939-20131111020445/@comment-173.67.254.144-20131205010210

I think that Ruby and Yang are both blood related but their dad got remarried after their mother's death. At the time Ruby was already in signal (don't know if Yang was or not since it hasnt been said if she did or didnt go there) so she kept her mother's name and Yang took their step mother's name. Implying that their family chose to use the mother's name and not the father's.

But thats just my opinion.