Board Thread:Spoilers!/@comment-26612471-20150712013347/@comment-24674051-20150714145930

Just rewatched Desperate Souls last night. When Rumple became the dark one, he immediately descended into the darkness. But if you look at his character right before the transformation, he was a coward, and had been forced to kiss a man's boot (either that, or lose his son early). He was stripped of his pride. Also, when he was sharing with Bae about stealing the dagger and taking the Dark One's power, he already had the grandiose ideas of stopping the war for everyone, and being able to not be afraid of anyone. His motives were selfish from the very beginning.

Emma did not want (nor need) the power. She took the DO and attached it to herself in a truly heroic and sacrificial manner. I think that may very well color how she responds to the darkness.

Another interesting comment is that, when Rumple killed Zoso, he asked him why Zoso tricked him into killing him. Zoso responded that the power of the Dark One is a great burden, and now it was Rumple's to carry. Which I would take to mean, given what we know now, that Zoso, at the end, was just like Rumple in knowledge of where the curse was taking him, and knew that the only way to avoid that was to pass the burden on.

All of that to say that I don't think Emma will completly descend into the Darkness immediately, though I do think she will become much darker, and she is being set up as the Big Bad for 5A.