[Warning: This story contains spoilers from Thursday's "Born Again" episode of History's Vikings.]

The bloodshed keeps coming. After saying farewell to Jessalyn Gilsig's Siggy just two weeks ago, Vikings parted ways with another original series castmember during an unexpected episodic twist on Thursday.

When series creator Michael Hirst first conceptualized Athelstan (George Blagden), he was a device to bring Western audiences into a pagan world. Before long, he became one of the show's most complex characters thanks to his inner conflicts and religious debates, and served as a mediator of sorts between the Vikings and those they sought during their raids.

That all came to an end Thursday when Athelstan finally found God again. The priest publicly declared his convictions by throwing the arm ring Ragnar (Travis Fimmel) had gifted him into the ocean, right when the Vikings learned King Ecbert (Linus Roache) had slaughtered their people back in Wessex. Despite Ragnar's attempts to protect his confidante, it was too much betrayal for Floki (Gustaf Skarsgard), who slaughtered the priest in a bid to "save" Ragnar.

The Hollywood Reporter caught up with Hirst and Blagden for their takes on Athelstan's final journey.

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Why was now the time for Athelstan to go?

Hirst: When I started writing the bible for the season, I realized I needed to resolve Athelstan's situation — that I could no longer go on showing him torn between two cultures and faiths in a continued spiritual crisis. It would be just going around in circles. I thought it would be an amazing thing for him as a character to recover his faith. What joy that would bring him. What relief. What certainty of a better life in death. Then I had to say, well what does that mean? Is it plausible that an ex-monk who has recovered his belief can live in a pagan society? To which the answer is obviously not. And the logic also pointed to the fact that Floki now was so desperate to save Ragnar from the influence of Athelstan that he was spreading the word to other Vikings that they ought to get rid of him. So I came to this terrible, terrible conclusion that I would have to kill my friend George.

Blagden: Michael sent me this five-page-long email explaining why he needed to make that choice this season. It was a lovely email explaining how Athelstan had always been one of his favorite characters and he didn't want to overextend it. He was saying the most successful characters in television are the ones that never outlive their sell dates — in terms of knowing when a character has experienced all they need to experience in that particular story and knowing when to close the book. I totally agreed with everything he said, that this felt like the moment in which Athelstan had come to the end of his journey.

If Athelstan knew about his son would that have changed his view of martyrdom; could he have brought him back to Kattegat?

Hirst: There was no question of him being able to bring the baby back because the baby, Alfred, becomes one of the most famous kings in English history. He becomes Alfred the Great. Historically speaking, he fights against Ragnar's sons. So it was clear the baby had to grow up in Wessex and had to become, in due course, king of not only Wessex, but of England. Just as Eckbert says he will.

Blagden: That is the most tragic part of that whole relationship, that Athelstan never knew that he had a son. We saw in episode five the conversation between himself and Ragnar, where they talk about marriage and children. Athelstan said, "At least you have children." It precursors this fact that Athelstan becomes a father and never knows it. Had he known he had had a son, it may have changed his outlook on life. But that's the beauty of life, right?

What went into filming the death scene itself?

Blagden: In the room at the end, with Gustav and I, it was very connected. We were very present with each other and very much on the same page about what we wanted to achieve in this neutral understanding between the two characters. The comprehension and a mutual respect for each other's religions as well.

Hirst: When I first wrote the episode, I don't think there was a burial scene; the burial scene came out of Travis and I spending quite a lot of time talking. He wanted to have a scene put in which he says farewell to Athelstan. Then it became a major scene. By the end of six we were already kind of on the water going toward Paris, so I pulled that back just to make the statement that this episode was a kind of standout episode to mark the death of Athelstan — because he was such a pivotal, wonderful, central character in the show that it was only fair that I did that.

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Without Athelstan, who will Ragnar rely on to guide him in Paris?

Hirst: In episode one of season one, Ragnar talked about meeting a Wanderer who told him about sailing to England and had filled his imagination with tales of other countries and other civilizations. It's this wanderer, Sinric (Frankie McCafferty), who is going to reappear in Ragnar's life and help him to Paris.

What kind of lasting affects will Athelstan's death leave?

Blagden: Travis has always said that Athelstan is the only one Ragnar really trusts in season three. He's had a lot of fractured relationships with pretty much every other character in the show: his family, his ex-wife, his new wife, his you brother, his cousin. The fact that that has now vanished before his eyes leaves him open to danger and leaves a big weak spot for him as a character.

Hirst: It affects Ragnar at the deepest level. The first acts that he does afterward, when he shaves his head off is actually partly (an homage) to when Athelstan steals the knife in the first season and you think maybe he's going to try and stab Ragnar, but no. He gets a bowl of cold water and he starts to shave his head and re-create his tonsure. It's partly a tribute to that when Ragnar shaves his own hair. But what he's also saying is that he's a changed man. He inevitably becomes a darker figure who isn't going to trust people. It's not just Floki. Floki is one amongst many Vikings who could have killed Athelstan. Of course deep down Ragnar knows he is going to get revenge once he knows who did kill Athelstan, but he doesn't talk about it straight up because he has more emotional things to think about. Moving forward, that becomes a very important issue. It's had a profound effect, initially inwardly but then more and more outwardly and in his behavior.

How will it affect King Ecbert, who also loved Athelstan?

Hirst: There is going to be a huge payoff of that relationship in an unexpected way, but it's quite a lot further down the line.

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Any parting words?

Blagden: It was sad to leave Vikings; it's a really original show. I'll have to find a way of sneaking back on the set in this upcoming season four and maybe be a background artist — see if anyone notices me!

Hirst: That was the hardest, most emotional and emotionally difficult episode that I've written on Vikings. I was losing myself, I was losing a character who had become a friend and then I was losing an actor who'd become a friend from a fairly tight knit group of people. I've lived day in and day out with Athelstan and Lagertha (Katheryn Winnick) and Ragnar. They're real people to me. So to kill one of them, to be responsible for the death of one of them, is actually strangely really hard. I miss him to pieces. Not to say that we won't get glimpses of him in the future, I can't say, but I do miss him.

Vikings airs on Thursdays at 10 p.m. on History. Are you sad to see Athelstan go? How do you think it will change the tone of the show? Tell us in the comments section below.

Twitter: @amber_dowling