Elisabeth? 'Lyse'? von Blankenburg Lowenburg?

Why Marriage with Blankenburg and Westerburg

In order for Rorich, vogt von Hackenburg (Blankenburg) and Christian von Blankenburg to be brothers, this was the only logical way for this to be possible.

Winand married Lady (NN) von Blankenburg, they have a few children and then he dies (?). The Lady (NN) von Blankenburg then is married to Heinrich von Westerburg and they have children.

So, Rorich, vogt of Hackenburg (Blankenburg) and Christian von Blankenburg are actually half-brothers and cousins.