On the Nautiloid Commander Zhalk says "Take this ship or Zariel will have your head." or something close to that. What does Zariel have to do with the Absolute and obtaining the Astral Prism? I've gotten part way through act 3 and NO sign/word of Zariel other than comments from Karlack or Mizora that don't account to a row of beans. I'm curious what her tie-in is?