User blog comment:ChiisaiAoi/ENDED2/@comment-218.186.15.10-20130607162750

I'd just like to comment that I agree Karu is likely to be a legitimate Barsburg. Considering that he was enough of a threat for one of his own relatives to want to kill him off so that his (the relative's) son would have a better chance of winning the competition for the heir to the throne, and Millea, a concubine's daughter, apparently wasn't considered a threat (she wasn't even accepted by the Barbsurg royalty), I'm quite sure that Karu's mother was not a concubine.

So...yeah. Just my 2 cents' worth.