User blog comment:TheCarrotSaysYumYum/Why Lisanna is Fairy Tail's worst character~/@comment-5871436-20140105051124/@comment-24066070-20140106062753

Mira is currently becoming a demon (yes, she may be rescued by Natsu, but the process will still affect her in a way)

Elfman is about to "sacrifice his soul" since he can't think of anything else than beg for mercy.

So if the Sayla is gonna turn Elfman into a slave or whatever, she may just turn Lisanna in one as well while she's at it.

So the 3 of them becoming evil is possible and then they can all die in order to teach the FT members some real pain of losing comrades (this time permanently)

Seriously, I'd be disappointed if not a single FT member dies this Arc, since Tartarus is by far the most serious group of enemies they faced up until now.