Relationships are changing and morphing in the upcoming fifth season of ABC's Once Upon a Time.

'Once Upon a Time' Star Jennifer Morrison Admits To Feeling 'Exhausted' While Playing 'Dark' Emma

As Emma (Jennifer Morrison) becomes the Dark One after sacrificing herself to the darkness in the season 4 finale, her parents, Snow (Ginnifer Goodwin) and Charming (Josh Dallas) will do what they can to bring her back to the side of good.

Morrison, Goodwin, Dallas and many of their other co-stars sat down with Entertainment Tonight at Comic-Con (in a new video posted this week) where they discussed Emma's darkness.

How 'Once Upon a Time' Season 5 Will Be Like Season 1 Again

Dallas said that things are going to be "tough" for Charming and Snow as they grapple with Emma's darkness. "They spend a good part of their relationship together making sure that she didn't become The Dark One. And now she's become The Dark One, so I think you're going to see them go to some extreme and possibly questionable measures to getting her back to the savior that she is. And it's going to test their relationship too in a big way."

On the flip side, Rumple (Robert Carlyle) is dealing with no longer being the Dark One, and season 5 will be about how he deals with this in relation to Belle (Emilie de Ravin).

"Well, we don't know what's going on with him. It's a little hard for us to have any terribly in-depth conversations right now. The coma puts a little damper on things for now," de Ravin quipped.

However, there is still some hope left for Rumple and Belle in the future.

"I think it's going to be exciting to see their relationship like we've never seen it before," de Ravin said. "She's never been at this place in her life and never been in such a strong position, and he's never been unaffected or unconscious like he is now."

With dynamics changing, the new season will surely be a fascinating one to see unfold.

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