Who was the old vampire woman Sam killed?
The one who kept giving Julius orders. His Mother? A vampire nanny?
NO DAY BUT TODAY! - From Broadway Play "RENT"
Well you know, we weren't given more information than you.
From what we saw, Julius and this female vampire had a somewhat mother-son relationship. She seemed to have known Julius back when Dmitri held him in hight regards and for some reasons, she weren't pleased with Dmitri as the leader of the the Vamps.
But I don't know if it's all that important to know who this woman was. Julius cared for her and she was killed. It seems that Vanessa and Julius have 2 reasons to team up now : to get rid of Sam and Dmitri.