Board Thread:Questions and Answers/@comment-24098614-20160401113517/@comment-27086573-20160401124635

From the LN Vol.1, it is stated that the 7 clans offered the 7 women to marry the Black Dragon Emperor and then they were given the viralts by him. So yes, they were as good as queens to the Black Dragon Emperor, but after them no king is said to have married the vanadis and their territories are also called Dukedoms. But they rank higher then the dukes because they have viralts, but they have to remain loyal to the king or else their viralts will leave them.

Hence, they are above everyone else but below the king in rank..