The peace between Viking's Lagertha and Kalf won't last forever.

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Kalf capitalized on Lagertha's season 3 absence to usurp her lands and title, leaving the shield maiden high and dry. While the pair worked together on the Paris raid, their feud will not be forgotten as the Norseman sail into season 4.

What exactly will transpire between the two, however, is currently unknown.

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"Well how can I say what's in the back of a woman's mind?" series creator Michael Hirst told Zap2It. "I have to say, and probably you'd expect me to say this, that resolves itself in unexpected ways. I think people are going to be surprised. Obviously it has to resolve itself, but it's going to be unexpected. It's a thread that we're carrying over to the next season."

The History Channel series concluded it's third season on Thursday with the action-packed and nerve-wracking "The Dead." Vikings started filming for season 4 in early April and viewers may be treated to a longer season than normal when the series returns next year.

Click the video below to see a preview for the series' latest episode, "The Dead."

Tags: vikings television history channel