Oh boy! I sure DO HOPE they will explain her wicked motives in striking down the Omnipotent (after swallowing that demonic spawn, sadly not "the Demiurge" or more of her daughters herself) Ilias.
Generally it's commonly believed Lucifer (Helel, Heylel, Phosphorus, Lucipher, etc) was created first day and Michael/Mika'el after "him". Which is again ONLY reason I could see their wierd relationship in the series. It's more that obvious that Metatron "took the torch" of being G-d's favoured and overall Supreme Angel (w/his "twin") after "his" absence (it's NOT Michael, sic!)
NOW all that stupid confusion of "Lucifer being pre-fall name of Satan" (doh) comes from the character of Kasbeel/Kazbiel/Kazfiel, in the Gnostic take known as Horaios. His name was Beqa/Biqa or Akae - "Keeper of the Good Promise/Oath". They were NEVER similar characters! Satan and Mastema despite their somehow troubled loyalty were often seen serving G-d (as seen in the story of Job and Abraham), BUT Lucifer - the prideful original rebel WOULD NEVER EVER DO SUCH A THING!