Erik is Duke of Avamar. Since he married Lady Serria and appointed her Margravine of Avamar, he's not a Lord anymore, nor he have estates. I believe he cannot take estates until take a Lordship (since he cannot serve under a Lord being his Duke), but he can be Lord of regions outside his Duchy or just in Avamar?
Thanks in advance. Just wondering the hierarchical mess. Also, he's Royal - i don't know if it matters, but well, the mess would be more interesting. I don't believe he can serve another Duke, but... just checking.