Vikings’ Alexander Ludwig is certain about one thing he’ll do once the show comes to an end.

He’ll shave his head.

“This is coming off. I am so sick of it,” the Vancouver native says of the hair-on-top/shaved-sides cut that he’s sported for four seasons as Bjorn Ironside, son of Ragnar Lothbrok on the popular, sex-and-violence-filled History Channel series.

Maybe try growing it out, instead? “Maybe. But first I’m going to shave it the f--- off as a statement. THEN I’ll let it grow.”

Ironically, this approximation of a ninth century Nordic hairstyle looks pretty hipsterish in 2016. “Which is totally not me,” Ludwig says. “It’s such a douchy feeling, walking into a bar and it’s like, ‘Who’s this guy trying to be?’”

It’s a minor complaint in the big picture, Ludwig admits. A history buff, the 24-year-old has been biding his time on the series, knowing that Bjorn had a pretty sweet future ahead of him beyond being his father’s son (go ahead, Google it).

That time is now.

At the midway point of Season 4, Ragnar (Travis Fimmel) lost his battle for Paris against his brother Rollo (Clive Standen). The series then jumped ahead several years, to the return of a long-lost Ragnar, and various sons in the process of becoming kingly – most notably Bjorn.

“Bjorn is becoming the character I’ve long waited for,” says Ludwig. “I did my research. This is what I spoke about to Michael (Hirst, the series creator), and the kind of the season I was promised when I first signed onto the show.” Hirst hired Ludwig directly from The Hunger Games, where he played Cato, the bad guy from District 2, who fought Katniss in the movie’s climax.

“I couldn’t be more excited for the audience to see what’s going to happen, because it’s going to blow their mind.”

Admittedly, a lot of what’s on The History Network isn’t very historical – unless, say, you believe in ancient aliens.

But, apart from a bit of dramatic licence, the characters inVikingsare mostly actual historical figures. One example, Ludwig notes, was the surprise advantage Rollo had using crossbows against his former Viking brethren. “Crossbows had been around for a few hundred years,” he says, “so they wouldn’t have come as a surprise. But for the most part we stay close to the historical trajectory.”

He knows his Vikings. We talk about Bjorn’s desire to settle new lands in the Mediterranean (requiring him to come to terms with his father’s enemy Rollo), and how far the Vikings actually traveled. I mention I’d seen a Viking’s name carved into a stone railing at the Hagia Sofia in Istanbul.

“Halfdan the Black!” Ludwig exclaims excitedly, mentioning one of his sibling characters, played in Vikings by Jasper Paakkonen. “He was kind of the first to introduce graffiti.” Ludwig pulls up his sleeve and shows off a Norse rune tattoo that he and Paakkonen got together. “It means ‘brothers,’” he says.

The real Halfdan the Black was no relation to the Bjorn Ironside who’d become King of Sweden. He was actually the father of Harald Fairhair, the first King of Norway. “But that’s what the writers do,” Ludwig says. The characters did exist. But to enhance the drama certain relationships are changed.”

But the big conflict in Season 4, the last half of which debuts on Nov. 30, will be between Bjorn and his ruthless, misfit brother Ivar the Boneless (Alex Hogh Andersen). Despite being unable to walk, he has violent tendencies and ambitions, which Bjorn admits scare him.

“I love his character, it’s brilliant,” says Ludwig. “They don’t even know really what that name meant. It’s so hard to translate from that Old Norse to today. So 'boneless' can mean many things.

“But with the historical detective work our historians did, they concluded he must have had this disease that makes bones brittle (osteogenesis imperfecta). And it causes the whites of your eyes to go blue, which sounds so trippy.

“Again, there are other theories. But if you’re presented with different options, you’re going to take the one that’s the most dramatic.”

And the two sons of Ragnar are definitely on a collision course. “I’d say you can look forward to a similar relationship that Ragnar and Rollo had, in terms of the struggle for power.”

Twitter: @jimslotek

JSlotek@postmedia.com