Lagertha (Katheryn Winnick) is queen of Kattegat on “Vikings” now — but after a visit to the seer on the Jan. 4 episode “Crossings,” she knows her end must eventually come — and it will be violent. The queen was informed she will be killed by one of the sons of Ragnar Lothbrok (Travis Fimmel), but didn’t reveal which of the boys will be behind the death.

After killing Aslaug (Alyssa Sutherland), Lagertha clearly has a target on her back when it comes to Ivar (Alex Hogh), Ubbe (Jordan Patrick Smith), Hvitserk (Marco Ilso) and Sigurd (David Lindstrom). As the boys raise their Great Heathen Army to invade Wessex, let’s take a look at the sons and see if we can figure out which one will take Lagertha down.

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Ivar

It’s hard not to assume it’ll be Ivar the Boneless who avenges his mother. He’s clearly the most bloodthirsty of the Lothbrok boys — even his own brothers regard him as insane — but he was also the closest to Aslaug. While all four boys are mourning the death of their mom, the hurt and rage Ivar is feeling runs so much deeper: She is a major part of Ivar, just as uncanny as he is, and she taught him how to survive.

Ubbe

While Ubbe is a definite possibility, it was at Ivar’s insistence that he started plotting against Lagertha in the first place in “The Great Army.” It’s unclear exactly just how potent his rage toward his mother’s killer really is. Lagertha telling him he looks like a young Ragnar — which he really does — and allowing him to free and marry one of her slaves could make him a little less driven for revenge.

Sigurd

Nothing is ever all that clear with Sigurd. He’s not the crazy person that Ivar is, but he’s also not the leader Ubbe is. Instead, Sigurd seemingly just falls in line with Ubbe and will likely follow him wherever he goes. It’s enough to make you wonder if he’d kill Lagertha at his brother’s request — he was certainly prepared to kill her with Ubbe earlier in the season, though it never came to pass.

Hvitserk

Let’s be honest: It’s not going to be Hvitserk. After his time away with Bjorn discovering the Mediterranean, Hvitserk seems closer to his half-brother than ever. When confronted with the idea that killing Lagertha would also mean Bjorn must be murdered, Hvitserk confronts Sigurd with the idea that he would lose that particular fight. He’s essentially the odd brother out, among Aslaug’s sons, and least likely to deal the fatal blow.

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Bjorn

Now hold on, we know what you’re thinking. How could Bjorn (Alexander Ludwig) kill his own mother? It may seem crazy — but crazier things have certainly happened on “Vikings.” Besides, he’s a son of Ragnar and thus can’t be left out. While it’s seemingly impossible for Bjorn to kill his own mother, it’s not as if “Vikings” hasn’t caught viewers by surprise before.

As it stands, Bjorn could be accidentally responsible for his mother’s death. There’s also the question of Astrid (Josefin Asplund). While she may be loyal to Lagertha, it’s clear from “The Great Army” that she has a strong connection to Bjorn. When feelings get involved, nothing is really off of the table.

Will Bjorn be the man who kills his mother? While we don’t want to believe it, at this point it’s just too hard to figure out.

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Of course, the other major question is when will the death come. While we’re watching Season 4, “Vikings” is already long into production on its fifth season. Whether Lagertha will make it that far remains a mystery but it’s one we’re almost afraid to solve.

“Vikings” airs Wednesdays at 9 p.m. ET/PT on History Channel.

Posted by:Chris E. Hayner

Chris E. Hayner is equal parts nerd, crazy person and coffee. He watches too much TV, knows more about pro wrestling than you do and remembers every single show from the TGIF lineup. You may have seen him as a pro-shark protester in "Sharknado 3." His eventual memoir will be called "You're Wrong, Here's Why..." TV words to live by: "I'm a firm believer that sometimes it's right to do the wrong thing."