I really think eins is not real son. Only the king and tutor knew it.

I kinda figured that out in the anime. He is the only one out of 6 siblings that have a black hair. (●￣(ｴ)￣●)

I suspect that only he has the same hair as their mother or somewhat idk, did they show who the mother is? I forgot. Because like Bruno's hair is dark yellow right? So I mix of lil black, so maybe the mother has black hair Ō3Ō hmmm

The mother is yet to appear. I hope she will be presented cery soon. The queen who ascended to be by Viktor's side should ve interesting to knoe