What's ahead for Regina (Lana Parrilla) and Robin Hood's (Sean Maguire) complicated relationship on ABC's Once Upon a Time?

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As Regina and Robin proceed through the Underworld, their relationship will stay strong despite some complications coming up along the way.

Parrilla spoke with Variety about what's going on between Regina and Robin.

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"They're on fairly solid ground with one another. The conflict is Zelena (Rebecca Mader), even though she's no longer in their lives - she's back in Oz - some stuff happens down the road," she warned. "What we see with Robin and Regina is that they do have a very solid relationship; Robin follows her down there even though he doesn't have to, he's that gallant hero-thief boyfriend and he wants to protect her and he doesn't want to leave her side because he knows there's going to be a lot of people who are probably out to get Regina in this Underworld, so he follows her down there."

Delving into the conflicts they will face, Parrilla noted that Robin is the father of Zelena's (Rebecca Mader) baby, and this love triangle (of sorts) will complicate things.

"Robin and Regina will face some other conflicts as the season progresses; he's the father of this baby with Zelena, and that is something that, until it comes front and center and we have to deal with it, it's on the back burner--the number one focus is trying to get to Hook [Colin O'Donoghue]," Parrilla said. "But stuff happens down the road as the season moves forward with Zelena's character and her love for this baby, and what she ends up doing to try and get this baby back."

Parrilla also observed that Regina and Emma's (Jennifer Morrison) relationship has come full circle, and spoke on why she chose to follow Emma into the Underworld: "I think that ultimately Regina really values love and deep relationships, and she sees how important Hook is to Emma and being that Regina and Emma are family, she wants to help her in any way--they're best friends."

Once Upon a Time airs Sundays at 8 p.m. ET/PT on ABC.

Watch the promo for the next episode of Once Upon a Time here:

Tags: Once Upon A Time television ABC