So rose is the horseman of death?
Looks to be a horseman from the preview and her being famine doesn't make a whole lot of sense...I suppose having lucifer send a messenger he knew didn't have it in her to kill her was a ruse. Maybe she killed the actual messenger, breaking her seal, then assumed her place. But even if this is so, why would it now be in lucifers interest to sell her out? If she is a horseman than they only need to find one more; having her as a mole would presumably take him straight to famine...
Maybe shes another type of angel after her own ends? Maybe she's a demon? A rogue horseman intending to steer events in such a way as to undermine Lucifer? Or maybe he just has run out of patience with her...who knows at this point?