Halfway through its fourth season, Vikings began to prepare viewers to say goodbye to its star, Travis Fimmel, who plays the enigmatic Viking leader Ragnar Lothbrok. The show's creator Michael Hirst has always made it clear Vikings was the tale of Ragnar and his sons, and that it would (likely) continue on past Ragnar's ever-imminent death. And in Vikings' midseason return, the History drama set the stage for this transition by putting Ragnar's sons in the foreground of the series, having jumped forward in time to find them now grown and ready to lead their own adventures.

But of Ragnar's younger sons, there is a clear breakout star: Ivar the Boneless, as played with a chilling passion by Alex Høgh Andersen. As history buffs know, the historical Ivar became even more legendary than his famous father. But unlike Ragnar, who was driven by his curiosity and desire for viable farmland, Ivar is ruthless in his pursuit of success.

TVGuide.com spoke with Andersen about taking on the complicated role, whether Ivar is a sociopath and how he became the greatest Viking of all time.

What kind of person do you see Ivar as?
Alex
Høgh Andersen: First of all, he is a poor kid who just needs to be loved in the correct and rightful way. He's been abandoned by his dad. His mother has been suffocating him with love because she was compensating for his disease. And living in Viking culture with that disease is a huge challenge. Personally, as an actor to take on a role like this is just extraordinary. But really, he's just a poor kid who needs love. And yet, he's got a violent personality and a few anger issues as well. He's compensating every single day for his disease. That's really who he is.

Where do you think the violence in Ivar comes from?
Andersen:
That's actually a very good question, because I'm not quite sure about it. I think it's just something he's born with. And it doesn't help that he's grown up in a very dysfunctional family, being the youngest one and being so challenged, but I think it's something he's actually born with. Of course, Floki (Gustaf Skarsgard) understands that, and his mom as well. So for Floki to school him, I think he's been channeling that anger and violence into killing Christians. And that's definitely something you will see in Ivar in the future.

One scene that really stood out to me was when Ivar almost killed Margrethe because he was afraid she would tell people he was impotent. Do you think that, because of Ivar's physical disability, he feels that he can't show any vulnerability in order to be perceived as strong?
Andersen:
I think what that scene was about, and what his entire life has been about, is just him being accepted and being a part of the group, being a real Viking. There was literally a scene where he was sitting alone on the beach while his brothers were fishing. That has been his life. And so for him, to be able to have sex and the possibility of having heirs is a huge thing, and by that he could become one of the brothers. He could share her with them and he could be a part of the group. That's what it's all about. And f**king hell, that is taken away from him as well. And when I read the scene, I felt so bad for this poor dude because to me, it's obvious that he's really just a sad boy and is compensating every single day with the limitations that he's struggling with.

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When Ragnar returned to Kattegatt, Ivar was the only one of the brothers who didn't hold any bitterness towards his father. Why do you think that is?
Andersen:
Because he's smarter than them. Because ambition. I think Ivar puts ambition before anything else. He's very religious and was schooled by Floki, and so he knows that being famous has everything to do with getting accepted to Valhalla in the end, which would be the main goal in your life as a Viking. In Episode 10, I think I say something like, "He just wanted to be famous, so he shouldn't tell anyone about the settlement that got destroyed because that would screw up his goals." I think Ivar doesn't give a damn about that other stuff, that personal stuff. He sees the bigger picture and is smarter than his brother in that area.

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Ragnar wasn't around much of Ivar's life, so he knows his father mainly through stories and legends. When Ivar finally gets to spend this time with Ragnar, how does the reality match up to his expectations?
Andersen: I think when he sees him the first time, I think it's obvious to everybody that he's wrecked ... But when he spends time with him in England, he sees straight away that there is a method to all his madness and all that he ever did. He understands why he became such a famous Viking, because he's so intelligent. And Ivar has a great learning experience. For Ivar to observe his father in action is such a learning experience. And the same with me, when I was with Travis, just observing him working was a very cool experience.

What does Ivar learn from Ragnar that helps shape him into the legendary Viking Ivar eventually becomes himself?
Andersen:
I won't say too much because it's not out there yet, but he learns how to be independent in a completely different way than he has already experienced, because he is a very independent guy. But he also learns what's important and military strategy things: what's smart, what's not so smart, manipulating people, what really matters. He learns a lot of stuff that you can't learn yourself without getting it from experience. And that's what Ivar really needs because he hasn't had any experience with anything because of the disease. But he is very intelligent, so he picks it up very quick.

Floki played such a huge role in shaping who Ivar is. Are we going to get to see scenes with them together this season?
Andersen:
I had some great scenes with Gustaf, who plays Floki. It was an outstanding experience. And we loved our scenes so much, Gustaf and I. We have awesome chemistry. There are scenes where you will see our special relationship, and it is our special relationship. Floki is kind of a mentor, kind of a bonus foster father who stepped up when Ragnar wasn't there. He is very close to Floki. And Floki, I think, is the only person that Ivar really trusts.

How would you characterize Ivar's relationships with his brothers? Is he close to any of them?
Andersen:
I think he has the best relationship with Ubbe, because he takes care of the family and takes care, as much as he could, of Ivar. And Jordan Patrick Smith, who plays Ubbe, we've been talking about creating this relationship where Ubbe has been Ivar's legs in a way. I think he loves them. He won't admit it. But it's not overwhelming love. I think he's a little bit of a sociopath as well. He doesn't really know what love is - real love. He also has a huge problem with being an outsider. He never really got close to them because he has simply not been there for all these lovely moments the brothers had together. He's always been a lone wolf dragging himself around, and he's very jealous of them as well. I feel like he is an outsider and he's very lonely.

How will we see Ivar grapple with or potentially come to terms with his disability this season?
Andersen:
What I think his trip with Ragnar will do is give him some ambition and the ability to believe in himself and his strength. And he really needed that. You will see that he will get a lot stronger and he will keep fighting his disease like he's always done. And in an upcoming episode, you will see him try something very drastic to fight the disease. That's a tiny spoiler!

What can you tease about what happens once Ivar and Ragnar arrive in Wessex?
Andersen:
It's just a father and a son trying to pick up the pieces that they've lost and put them back together to become what they are: father and son. It was outstanding to shoot and I think it's going to be outstanding to look at as well.

This is Ivar's first journey abroad. What is his reaction when he sees this whole other world?
Andersen:
He's excited. He's very, very excited. He's been waiting for this moment for such a long time. What it basically is is Ragnar putting hope in him. I think if Ivar had kept living the life he had been, he would have become suicidal at some point. There was no moving forward, no ambitions, no nothing. And that's what Ragnar does. He creates that momentum and change in his life, which he needed. And so it's a journey. It's an adventure.

Vikings airs Wednesdays at 9/8c on History. Watch an exclusive sneak peek of this week's episode in the player at the top of this story!