When “Vikings” creator Michael Hirst set about telling the saga of the famed farmer-turned-king Ragnar Lothbrok and his equally (if not more) famous sons, he always knew his leading man would reach an endpoint. That moment came in the fourth season of the History series when Ragnar (Travis Fimmel) met his end in a poisonous pit of snakes, unleashing a bloody chain of events that included his first wife Lagertha (Katheryn Winnick) killing his current wife Aslaug (Alyssa Sutherland) and taking over Kattegat, while his sons banded together in The Great Army to exact revenge on the Saxons responsible for their father’s death.

“I knew that in some ways killing Ragnar was taking a chance; I was told that to kill off a major character might be problematic, but I didn’t worry about it,” Hirst tells Variety. “The other sons all have some aspect of Ragnar in their characters, for good and bad. It’s a bit like the Beatles: they were four individuals who were in some ways one. Season 5 is all about shifting allegiances and The Great Army falling apart and the brothers fighting against one another. This season we see them often at each other’s throats.”

Those themes of conquest, revenge and redemption pick up in the fifth season’s two-hour premiere, “The Departed,” as Ivar the Boneless (Alex Hogh Andersen) leads the army on yet another top-secret raid, Bjorn (Alexander Ludwig) separates from his clan to raid the Mediterranean and Harald (Peter Franzen) makes his move on Kattegat. Meanwhile Jonathan Rhys Meyers, who joined the cast late last season as the mysterious Bishop Heahmund, begins plotting ways in which to finally take the great Viking army down in the wake of King Ecbert’s (Linus Roache) death.

Ahead of the premiere Variety caught up with Hirst to explore what a Ragnar-free season looks like, to delve into the show’s ongoing reinvention through the addition of Jonathan Rhys Meyers as the new feared Christian, and to preview the ultimate battle for the Vikings’ home base, Kattegat.

Was it important to bring in an established name to replace Travis Fimmel on the call sheet?

Johnny was the one and only person we thought of because we know him very well. I described what kind of a character we needed and everyone agreed. He’d just been in “Roots” for History and they’d really liked working with him. He’s dangerous as an actor, maybe even as a person, I don’t know. He’s an unpredictable player, and that’s what we needed.

What kind of adversary will Jonathan Rhys Meyers be to Ivar?

I’ve heard about some protests from Christian clergies in the States that my Christians were too feeble when fighting against the Vikings, and that their best dude was the monk Athelstan [George Blagden], so no wonder they got beat up. I thought that was slightly unfair criticism, but at the end of four with Aethelwulf [Moe Dunford] in retreat and the Saxons beaten I knew I needed a Saxon leader or warrior who could potentially stand up to Ivar and the Vikings. My historical research told me about these warrior bishops who were real people. Bishop Heahmund was a real bishop and warrior who died in battle and I knew as soon as I was on the trail of this character who was a forerunner of the Knights Templar I knew I had someone who could stand up to Ivar. You can tell when the characters are fighting each other in York that they recognize something about each other and their stories become more interlinked as the season goes on. It was evening up the playing field to introduce someone who was as formidable as anyone on the Vikings side.

What kinds of challenges does having a character like Ivar the Boneless, who can’t walk, pose when it comes to crafting these battle scenes?

I probably couldn’t have written that character earlier on in my career. I couldn’t have made this poor crippled guy a Viking hero and one of the most famous men in the Viking world. It’s a creative challenge and as a writer and creator you need those challenges. We came up with some amazing solutions. Ivar doesn’t think of himself as crippled unless he wants sympathy. He thinks of himself as a strong warrior and he proves that. He’s a very complicated young man. It’s incredibly ironic that the most famous Viking of all time and by reputation the cruelest Viking of all time should turn out to be a cripple. Writing the character was a challenge as he’s a great warrior at the same time as being unable to walk. As we get into Season 5 you see how he deals with that and the various ways he finds of moving about — some of which are ingenious and all of which point out his disabilities. So however cruel he is you always remember he had the most terrible childhood and he’s got the most terrible disability so you don’t actually ever really lose sympathy with him.

These Vikings men and women lived short lives; what was it about Floki (Gustaf Skarsgard) and Lagertha that gave them longevity now that the rest of the original cast is gone?

There’s a constant negotiation going on in my mind about who will live and who will die. There are certain things I knew [like] Ragnar had to die more or less at a certain point. I know when others have to die because it’s appropriate to historic circumstances and the bits we know about them. But there are other characters that are more free spirits. To kill characters like that at a certain point would be ridiculous or self-defeating because I need them for something further down the line. Sending Floki to Iceland was not an entirely difficult idea, as he got tired of the world he was living in. He’d lost all the people he loved. He was tired of the battle between Christians and pagans. He wanted to find a purer world where the gods were so he just cut himself adrift in a boat and ended up in Iceland.

Lagertha existed but we don’t know how she died. She’s had a hell of a life, and had everything thrown at her. I’m constantly fascinated how as a woman she deals with all of these issues. I do believe it’s more difficult for a woman to deal with these many, many personal political power issues than for a man. So I root for her a lot and want to know how she’s going to deal with the next issue. I don’t want to kill her arbitrarily. I need her around. Unless I have really good reason to kill her, I’m not going to.

Given that you write everything yourself, do you have any females in your life that you bounce ideas off of when writing that kind of female character?

I just hope my daughters watch it and are pleased by the depiction of Lagertha and not that they necessarily learn something, but are thrilled that their father has managed to depict this wonderful female character who is anything but a token character. All of the women characters are different on the show and I’m proud of that. From “Elizabeth” onwards I’m interested in female characters. I did my PhD on Henry James and he loved writing about women. The great thing about the freestanding characters like Lagertha is that they can surprise you, which may sound weird, but someone like that can deal with a situation in a way that initially I hadn’t thought of. That’s how real she is to me.

How does Rollo (Clive Standen) factor into this season?

Who wants to lose Rollo completely? It was always in the back of my mind to bring him back and I do bring him back, and in a totally unexpected way with some unexpected revelations. Fans should be pleased to see him again and we had to work with Clive’s other commitments, but he was very, very keen to come back. These early pilgrims, the first cast that I had, I obviously love them and they were with me for season after season. I love their characters and it’s always painful to lose them, so I will always grasp the opportunity to bring them back if it’s realistic and it works. It was great to bring Clive back.

How much of the Christian narrative follows Alfred the Great (Ferdia Walsh-Peelo) this year, considering his own historic future?

Alfred is a sickly young man and at this stage you cannot imagine how that youth eventually became known as Alfred the Great. The Saxons and the kingdom are in the greatest peril and you just don’t know how things can resolve themselves in a good way. Except that King Ecbert, his grandfather, recognized something about Alfred and singled out him as special. He educated Alfred in philosophy and warfare and he had a feeling that Alfred might be the future. You never can tell how fate will play out but the audience is watching and wondering all the time whether this rather sick young man is going to be able to redeem himself and be reborn as one of the few kings in history who was called the great. At this stage it’s very tentative as to how long he’s going to survive.

This season is very much about raiding and exploring, but by the end of it the biggest battle is back at Kattegat. Why will that always be your base?

Shows have to have a center. The first thing we built back in the first season was the great hall at Kattegat. It is like the spiritual center of the show. Of course you go back to that because it also represents the center of power for Ragnar’s family. So even though the show takes us to Morocco and to Iceland and previously they’ve gone to Frankia, they’ll always come back to their power base. And their powerbase is their spiritual home as well. The actual location, Kattegat started as one, maybe two buildings on the stage and four on the back lot. It’s now like two acres on the back lot and four stages for the buildings. It’s huge now. It is a huge trading station instead of a small Viking village. The battle for Kattegat is always going to be intense between the sons because that’s where their father ruled. Ragnar didn’t like to be king particularly but he was and now they want to be. It’s a father-son thing. You wait until you see episode 510. That battle for Kattegat is the most extraordinary thing we’ve shot so far.

In your head does this show still end with the Vikings reaching North America or have you since rethought that?

It is still in my mind to finish or to get where I always said I wanted to get to with this show, which is North America.

“Vikings” premieres its fifth season Wednesday, Nov. 29 at 9 p.m. on History.

This article has been edited. A previous version accidentally omitted a portion of the interview.