Guild Wars 2 Giveaway: Trivia #17

Tyria is waiting for you. Hi everyone, today's ticket to Tyria, Trivia #17 requires a little bit of research if you haven't followed Guild Wars 2 Diary. If you have, you won't even need to think about it. It's that simple. 

Today's question:
"Who needed Queen's royal blood? And which episode was it?