Why Morgana loves Season 4 of Merlin: 'I get to be a LOT evil.'

Remember that sweet and somewhat spoiled girl who was King Uther's ward in season one of Syfy's Merlin? Well, she's gone, and the Morgana that's replaced her is dripping with evil and back with a vengeance when the show's fourth season premieres tomorrow at 10 p.m. on Syfy.

Morgana is "just better in every way," said Irish actress Katie McGrath, who plays Morgana. "Fourth-season Morgana is this confident, self-possessed, self-reliant, driving-force-behind-her-own-story, confident woman. And to be able to play that when I'm totally not like that in real life is such a wonderful thing. I can't even tell you. Coming to work is a joy."

And she gets to be more than a little bit evil.

"I get to be a lot evil. It's so much better," said McGrath with relish during an exclusive interview with Blastr.

"I think the fourth season is where you start to see the telling of the legend as you know it. You start to see Arthur becoming king, Guinevere becoming queen, Merlin becoming this great sorcerer, Morgana becoming this sort of dark, evil presence," she said. "It's more grown-up. The producers are—rather than sort of resting on their laurels and accepting that they had a formula that worked and staying with it that might have gotten stale—they evolved it every year, and season four is exactly that. It's just gotten bigger, bolder. It's more filmic. We're shooting on 35mm film. All our sets are bigger. Our locations are more vast. Our cast is bigger. It's our most ambitious yet, and I think to their credit they've really managed to pull it off. There was no sleeping to be had for eight months."

As far as specifics about the upcoming season, McGrath gets cagey.

"Well, I will say that possibly in the fourth season you might see the evolution of the love triangle between Arthur and Guinevere and Lancelot. That might come in. I'm not saying it definitely will, but it could. You might see more story about the sword and the stone. Again, can't tell anything, but that might happen. And you might possibly, possibly see the evolution of some prince into some type of king. Again, not saying anything," she said with a laugh.

"What's amazing about Merlin is that it gives you all those parts of the legend that you know and you love, but not how you expect it. It's this new twist. Even if you know the legend, and even if you are so familiar with it, you can still watch Merlin and enjoy it and find something new," McGrath added. "That's the thing about Merlin, it never plays out like you expect. You can't take anything on faith, and nothing is ever as it seems, and nobody ever really dies in Merlin."

In fact, expect Merlin and the villainess Morgana to surprise you a lot and through at least one more year. Merlin's been picked up for a fifth season.

"I know the producers as well didn't want Morgana to be this very two-dimensional bad guy. I think it was very important to everybody that in a way, you see her point of view. You sort of understand. While you may not agree with how she goes about it, you can almost see where she's coming from and how she's been driven to what it is that she's ended up doing. I mean, for her on season four, she's pretty much entirely running on revenge. That's all she's got, and I think her reckoning is going to come at some point, and I think that's going to be possibly later in season five, because right now all she wants to do is to make everybody pay for how she's been treated and what has happened to the people that she loves," she said.

"I think every story is only as good as their bad guy. It's only as good as the person that drives forward the story and drives forward the heroes. And I think that's what Morgana does. ... So essentially what I'm saying is that it's my show. You may think it belongs to Colin [Morgan as Merlin] and Bradley [James as Arthur], but it's actually my show. It's really called Morgana: The Merlin Years. But we don't tell Colin that, because he's very sensitive and we don't want to upset him," joked McGrath.

Merlin airs on Syfy on Fridays at 10 p.m. ET.

Are you ready for Morgana to embrace the dark side on Merlin?