[WARNING: The following contains spoilers from Sunday's Game of Thrones episode "The Gift." Read at your own risk!]

After Sunday's episode, Melisandre (Carice van Houten) may have become the most hated person on Game of Thrones. And that's no easy feat considering that two of the three masterminds behind the Red Wedding are still alive.

The red priestess, however, wants to kill a child — and not just any child. She wants Stannis Baratheon (Stephen Dillane) to sacrifice his own daughter Shireen (Kerry Ingram) to the Lord of Light to bring better fortune to his forces while they march to Winterfell through a fierce blizzard. Asking a father to kill his own daughter — one he had saved from dying of greyscale by hiring the best healers in the world — is too much, even for Melisandre. How could she?

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"I know, man, tell me about," van Houten tells TVGuide.com. "It was quite tough when I read it. It was quite tough to play it. It was intense. She probably thinks it's really not looking good for her to say this. She's always had this as a backup plan, I think, in case everything would go wrong, and I think she feels like we're really going in a really bad direction here. She only does this because it's the only way."

Part of the problem is that Melisandre's god R'hllor, aka the Lord of Light, is a grim and demanding god. He requires blood sacrifices, and the more blood of kings running through the sacrifice's veins, the better. This year, we've already seen Melisandre persuade Stannis to burn Mance Rayder (Ciaran Hinds), the King Beyond the Wall, and in an earlier season, Melisandre used leeches full of blood from the royal bastard Gendry (Joe Dempsie) to cast a spell on three of Stannis' enemies, two of whom have since died.

Since Melisandre believes Stannis to be the One True King of Westeros (besides being the heir to the throne after his older brother King Robert died), therefore his daughter has the blood of kings in her. "I think she knows what she's asking of him, that it's not going to be easy. Therefore she is so persuasive and so clear that there is only one way. Otherwise, everything will fall. More lives will be lost. This is the ultimate sacrifice."

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While the actress understands that many will think of Melisandre as a cold-blooded killer, she only kills because of her devotion to the god and his path. "That's the way I try to play her because it's boring to play a killer that's just a psychopath. That's a different character, I think," van Houten says. "The fact that she thinks what they have to do is for the better, that's scary enough as it is. These big villains as we know them, they don't see themselves as villains. They see themselves as heroes."

Earlier this season, Melisandre caused another outcry for a far less violent act. She stripped nude and attempted to seduce the new Lord Commander of the Night's Watch, Jon Snow (Kit Harington). Although he refused her (still pining for his lost love), Melisandre had the last word, echoing his dead lover's catchphrase: "You know nothing, Jon Snow."

The fans lost their minds. "I saw the reactions on Twitter just about me coming close to Jon Snow in any way. It's insane," the actress says. "They were like, 'Die, b----! Go away! Get your hands off Jon Snow!' They were so, so angry."

Melisandre's acts don't always lead to death. Not directly anyway. The last time she had sex that we know of was with Stannis. And then she gave birth to a shadow monster baby with his face that then went off and killed his brother. Could her biological shadow clock be ticking again, sensing some greatness in Jon Snow?

"I'm sure she feels there's something about him... like it's still in her subconscious," van Houten says. "We're not showing clearly what he represents to her. I think it's still quite blurry. She still wants Stannis on the throne, she's still devoted to Stannis. Of course there's also some male-female chemistry or attraction from her to [Jon Snow], but she's not that kind of girl. I don't think she's just interested in having sex with him, that she's necessarily out to get guys. That would just be a nice extra that he's good-looking."

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Getting her dirty, mystical mitts on Jon Snow aside, fans are probably the most outraged with the fact that Melisandre dared utter, "You know nothing, Jon Snow," that classic line the now-dead Ygritte (Rose Leslie) would say with equal parts condescension and affection. Although van Houten can't really explain why Melisandre, having never met Ygritte, would quote those exact words to him, the actress was able to make some sense of it to herself.

"Even if you wouldn't think [there's] anything behind it, it's just a great line for her because she knows so much," she says. "It's a very mean tease, a mean thing to say. Whether it actually means more, I cannot tell you now."

Clearly R'hllor works in mysterious ways, even to Melisandre, who isn't quite in control when it comes to whatever Jon Snow is awakening in her. That raises the question then if the way she's been reading the signs in the fires has been correct all along. Is Stannis the One True King?

"She's been pretty spot-on for a long time, I think, but like for any human being, people make mistakes," van Houten says. "It could be wrong at some point. I don't know. We know Stannis didn't let her come to the Battle of Blackwater. That was a mistake for him. We haven't seen huge mistakes yet."

This then brings us back to her interpretation of Stannis' dire situation... and its tragic solution. "It's terrible to say all of this stuff because it would probably be one of the worst things you've seen on TV ever if it were to happen," the actress says. "The suggestion alone shows how devoted and serious she is about her goals and about getting Stannis on the throne. If fans are angry at [her and Jon Snow], I wonder what's going to happen with this episode. I don't think I'm going to get any more sympathy votes because of [Melisandre's] suggestion here. It's good that I don't really have red hair."

What do you think of Melisandre's reading of the signs? What should Stannis do?

Game of Thrones airs Sundays at 9/8c on HBO.

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