Will newly "Dark" Emma (Jennifer Morrison) of ABC's Once Upon a Time pull some of the show's reformed villains back to the dark side?

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Once Upon a Time stars Colin O'Donoghue (who plays Hook) and Lana Parrilla (Regina) spoke with E! News about how Emma's darkness was going to affect their characters.

Hook is going to do whatever it takes to get the real Emma back, according to O'Donoghue.

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"It's awkward, because he spent so long trying to kill the Dark One and now he's going out with her," O'Donoghue said. "Look, Hook loves Emma and he wants to try and protect her heart at any cost. He spent most of last season trying to save her from the darkness, not to let her go, because he knows what that's like. Unfortunately she's now dark so he's going to try and fight to bring her back to who she used to be."

As fans will recall, Emma sacrificed herself to the darkness in order to contain it, leaving behind only a dagger with her name on it. It is now up to Hook, Regina and Henry (Jared Gilmore) to bring her back, but will Dark Emma persuade them to the dark side first?

"I like that idea," Parrilla said. "The Dark One is the most powerful, so [Regina] has to be extremely strategic in how she is going to approach this new Dark One. Stepping into this role of being the hero/savior is new for Regina. I don't know if she's going to be very comfortable in being that person in everyone's lives or having to now be the new savior but it will be fun to see how she accepts that or denies it and what she does with this new role."

Season 5 will pick up right where it left off in the season 4 finale, with Emma's disappearance.

Once Upon a Time season 5 premieres Sunday, Sept. 27 at 8 p.m. ET/PT on ABC.

Tags: Once Upon A Time television ABC