Here, mish mashed and photoshopped to within an inch of its life, we have the lineage of the royal family. Or at least the parts of it that we meet in SIREN.
Note: Vine silhouettes were downloaded from GVL, here, and all awesomeness goes to them for making such cool brushes. Also, I apologize if this is too small to make out all the nitty gritties. I considered posting it in its original size, but that...would have been comically large.
So, as you can see, the nobles that we meet actually come from three significant families. The younger members consist mainly of a platoon of cousins. However, Duchess Lorraine is a blood relative to Prince Aden only (through their mothers--and female relations are hardly important, in the grand scheme of things, amirite?). Princess Ysbail and Lady Rhosyn are related, but are otherwise only tied to the others through Ysbail's marriage to Aden.
The main family name to be concerned with is 'Hightower.' They are the most powerful family in Gandon, and the main source of consternation among the rebels--whom we shall meet on another day.
I realize that this is all rather meaningless if you haven't read the book. So...you should maybe read the book. Lorelei, Once: SIREN.
And with that, I shall set drawing aside. At least until I have caught up to my word count goal.