Im Slow okay?!

I think the prince was killed, and Ryuu is Biebke's son. But there is a rumor that the late king was his biological father, which in turn makes Ryuu the rightful heir, and not whoever is on the throne right now (and chasing Ryuu and Daniel).
But the two women seemed to get along rather well, which would be a bit strange, if one is the wife and one the lover. So there might actually be more to it.