Board Thread:Character Discussion/@comment-25375217-20170529212214/@comment-25375217-20170602182732

Just noticed something else: the Black Fairy's death was identical to the "death" of the Serum Queen in the Season 5 finale. Granted, they were two completely different circumstances, but the effects are undeniably similar. The disintegration effect is common, but it's only been exactly like this twice--even when Emir was disintegrated in between Fiona and Queen's "deaths".

I don't know if she'll be back in Season 7, but I'm almost positive the writers intentionally left it open for her to return if they ever want/need her. The set-up is definitely there.