User blog comment:Derrmann/By Jove, I've got it! (Totally know why Ruby and Yang have different last names)/@comment-10390252-20131116190312

I'm thinking that Ruby's dad was a widower or divorcee who married Ruby's mother who died on a mission. Super bad luck huh? Even worse that left him with a 3-ish blonde-haired girl and an auburn-haired toddler to look after on his own.