Board Thread:General Discussion/@comment-26391241-20150511234157/@comment-24674051-20150512153343

I think that, yes, the dark one has Emma's magic potential. However, light magic is the antithesis of dark magic, so I doubt that the DO can use light magic. Also, Rumple, while he was tethered to the DO, seemed to be able to somewhat control the DO, so maybe it's more like Emma has access to the DO, but that access has a cost.

Emma is no more dead than Zoso or Rumple. But she is definitely different.

As for leaving the dagger behind, it was a final sign of trust in all the people there. Unlike Rumple, who could not trust even Belle or Bae with the dagger, Emma is saying that she trusts that they will be there, and not abuse the power. The only person that I would worry about getting the dagger would be Zelena.

I think that we will see in the premiere someone (probably Regina, Snow, Hook, or possibly Rumple) pick up the dagger and summon the Dark One.