For no strong reason in particular other than the fact that the Wikipedia pages for Blackadder were slightly minimal in terms of family members of the Blackadder family, I decided to track down whatever info I could and make a family tree.
Behold! The family tree of ALL the major characters from Blackadder, as best as I could work it out.
Blackadder Family TreeIt's a big picture; you might have to download it to see it.