The following interview contains spoilers for “Once Upon a Time” Season 5, Episode 12, titled “Souls of the Departed.”

“Once Upon a Time” returned from its winter hiatus to celebrate a major milestone — the ABC drama has reached 100 episodes (and been renewed for Season 6), and it marked the occasion with an installment that brought back a number of familiar faces, from Emma’s (Jennifer Morrison) dearly departed ex Neal (Michael Raymond-James) to Giancarlo Esposito’s Magic Mirror.

While the hour saw our heroes embark on a quest through the Underworld in search of Hook (Colin O’Donoghue), it also shone a spotlight on Regina (Lana Parrilla), flashing back to her darker days as The Evil Queen and finally offering her some long overdue closure after she sacrificed her father Henry (Tony Perez) in order to enact the Dark Curse against Snow White (Ginnifer Goodwin) and her loved ones at the beginning of the series.

The episode showed Regina’s first meeting with her father since killing him, a scene that Parrilla admitted was “a very heartbreaking moment, because we’ve never really seen how the death of her father has affected her over the years. Regina’s yes, temperamental and yes, very fiery, but she’s also very private about her emotions … the stuff that really touches her deeply, her deepest wounds, I don’t think she articulates much, and she doesn’t share those feelings and thoughts. So when we see her see her father for the first time, we really feel this pain that she’s been living with for so many years. I remember reading this scene and I was bawling reading it because I always wanted that for her, I always wanted her to have that closure in her life. We also get to see her see her mother for the first time after her mother died in her arms – poor Regina, she’s had a lot of tragic experiences, but she gets to really make amends with her parents and it’s a beautiful thing to witness and a real gift to get to experience.”

Variety spoke to Parrilla about the 100th episode and what its developments mean for Regina and the rest of her family — especially in regards to new villain Hades (Greg Germann), who has a particularly strong desire to get her out of the Underworld, for reasons that remain a mystery.

How does it feel to have a milestone episode like the 100th as a Regina-centric hour?

I felt so honored. I thought that it was the right time to close some of those doors in her life and the 100th episode was the perfect opportunity to do so because there were some of those pivotal experiences that really changed and shaped Regina – especially the death of her father. And her relationship with her mother has always been a tumultuous one, so to see these relationships come to some sort of resolution at this stage and being in the 100th episode… I think it was well-earned.

Regina has arguably had the most monumental evolution over the course of the show – looking back at her journey so far, what are you most proud of?

I’m so proud of her diligence and her fervent nature to constantly strive to be a better human being; I think that’s a really admirable quality. And that’s something we’ve seen over the course of these years, this constant fight to try and do the right thing. Although we love the Evil Queen and we miss her and I love that she gets to make these appearances like in the 100th episode – and there’s an episode that follows where she comes back again, in the 101st episode – we love when she surfaces, but when we check into present time and see where she is at this stage in her life, I think she’s quite an inspiration. Her evolution inspires so many people. One fan said this to me, and it’s something I always love to say: “Good can come from broken.” A fan came up to me and said, “I love Regina so much; she gives me so much hope and faith, to know that good can come from broken,” and I thought, “that’s really powerful, that’s really inspiring.” She’s really made an impact and has inspired so many – it’s an honor to play her.

By the end of the hour, we learn that it’s not Cora (Barbara Hershey) who wants Regina out of the Underworld, it’s Hades. What do you think makes him such a dangerous adversary, compared to the villains they’ve faced before?

I think he has the most power of any villain we’ve ever come across; he’s the god of death – it doesn’t get more powerful than that. He has zero remorse, he takes lives away – that’s what his job is, so for him, it’s just a snap of his finger, he could kill someone with a thought. And that’s terrifying, you have to handle him delicately – you don’t know what’s going to push a button or irk him and you have to walk on eggshells when you’re around him. He’s also kind of creepy – his hair goes up in flames! Greg Germann does such a wonderful job playing him – he has such a sense of humor and irony; he brings some comedic aspects to the role which I think are very refreshing. It’s such a dark drama – it’s a family show, but it’s a dark family drama – and it’s nice to have these lighter, comedic elements in such a dark character like Hades. He does a fantastic job.

Will Regina and Robin Hood’s (Sean Maguire) relationship be tested by the Underworld, given the people they’ve lost? Or are they on fairly solid ground?

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. 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. 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. 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.

Regina has become Emma’s conscience almost as much as her parents are, in many ways – what can you preview about their relationship as they work their way through the Underworld?

I think these women have come full circle from where they used to be, at each other’s throats for so long to then realizing that working together is probably only going to benefit them, because they’re constantly facing outside conflicts and challenges… I don’t know if it was intentional to grow together and work together, but I think it was at that hands of them both being Henry’s mothers; living at odds probably wasn’t going to serve them or their relationship with their son. So they kind of naturally gravitated towards being friends and working together and I think that’s what you see here, they are family at this point. Regina also feels quite obligated to help Emma for multiple reasons; not only is she family, but this all started with Emma becoming the Dark One, and had she not saved Regina from that dark swirly Dark One monster — I don’t even know what you want to call it — Regina would’ve been the Dark One, and that could’ve been very dangerous for everyone, because even though she’s now this hero, she was an Evil Queen for so long, who knows what would’ve happened if she had become the Dark One? I think what she feels is an obligation to help Emma – she feels like she owes her one, and she sees how much Emma loves Hook, and she wants that for her. 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. on ABC.