Board Thread:Spoilers!/@comment-25733960-20150223011533/@comment-24674051-20150225222909

And to say that Maleficent does not have a history with Emma is not quite true. Of all the QoD, Emma has actually faced off AND DEFEATED Maleficent (Season 1 Finale). Not much of a history, but enough to possibly either piss Maleficent off or earn her respect (or both).

And it may not necessarily be Emma actually turning to the Dark, but the temptation to go Dark. As Killian pointed out in the S3 Finale, there is a little bit of Pirate in Emma.