Table of Contents
Introduction: A Vow Sealed with a Kiss and a Blade
I remember the exact moment my understanding of Vikings was irrevocably fractured.
It was Season 4, Episode 5, “Promised”.1
Lagertha, the shieldmaiden who had become a symbol of resilience and righteous strength, stood in her wedding dress, a vision of a future finally reclaimed.
Opposite her was Kalf, the usurper who had stolen her home but seemed to have won her heart.
He was beaming, besotted, on the verge of having everything he ever wanted: power, respect, and the love of the woman he’d always desired.3
And then, in an instant that felt both glacially slow and shatteringly fast, she slid a dagger from her sleeve and drove it into his gut.1
The scene was a masterpiece of cognitive dissonance.
The beauty of the wedding dress, now stained with the blood of her groom.
The shocking violence of the act, juxtaposed with the tenderness of the final kiss she gave him as he died in her arms—a kiss he seemed to return.3
My immediate reaction, like that of many viewers, was one of profound confusion.
The simple answer—”revenge”—felt hollow.
It was a single, flat note in what was clearly a complex and tragic chord.
It failed to account for the genuine partnership they seemed to be building, for his desperate, life-saving actions in Paris, for his unadulterated joy at the news of her pregnancy, or for the profound sorrow that swam in Lagertha’s own eyes as she committed the act.6
This was my struggle.
How could Lagertha harbor what appeared to be genuine affection for a man she was methodically planning to kill? Was she a cold-blooded sociopath playing a long con, or was something far more intricate at play? For a long time, I tried to solve this by placing her motivations on a scale, weighing “love” against “ambition.” But the scale would never balance.
The act seemed to defy simple emotional logic.
The epiphany, when it came, was not an answer but a reframing.
I had been trying to separate two elements that were, in fact, fused together.
The turning point in my understanding came from the world of ancient metallurgy: the concept of Damascus steel.
This legendary metal was not strong because it was pure; it was strong because it was a composite, forged by folding and hammering together layers of hard, brittle steel and soft, flexible iron.
The final blade possessed the unyielding edge of the former and the resilient toughness of the latter.
This, I realized, was the key.
Lagertha’s psyche, especially in this moment, was not a choice between two opposing forces.
It was the product of them being violently forged together under the immense pressure of betrayal and survival.
To understand why she killed Kalf, one must stop trying to separate the hard steel of her ambition from the soft steel of her affection.
One must see how they were hammered into a single, unbreakable, and tragic whole: the will of a queen.
Part I: The Unforgivable Sin – The Usurpation of Hedeby
To grasp the brutal finality of Lagertha’s decision, one must first understand the nature of Kalf’s crime.
His usurpation of Hedeby was not merely a political maneuver; it was an existential attack on the very foundations of her identity, an identity she had paid for in blood, tears, and humiliation.
Context of the Betrayal
In Season 3, after leaving Ragnar and surviving an abusive second marriage, Lagertha had established herself as the Earl of Hedeby.
It was her own kingdom, earned through her own strength.
When she prepared to go raiding with Ragnar in Wessex, she placed her trust in her second-in-command, Kalf.8
She even playfully asked him to marry her before she left, a sign of their easy chemistry and her faith in him.3
He declined, offering to stay behind and safeguard her lands—a promise he broke almost immediately.7
While she was away, he conspired with her enemies and declared himself Earl.8
When she later confronted him, Kalf did not deny the premeditation.
He admitted, “The fact is you planned to betray me, and you must have planned for a long time”.9
He confessed that this ambition was intertwined with a long-standing desire for her, a paradox that defined their entire relationship: “All the time that I was planning on overthrowing you, I desired you.
I never stopped desiring you”.10
This was not a crime of opportunity; it was a calculated betrayal by the man she trusted most with the one thing she had built for herself.
The Existential Threat to Her Identity
Kalf’s sin was unforgivable because of what Hedeby represented.
It was not just a parcel of land; it was the physical manifestation of Lagertha’s entire post-Ragnar narrative.
First, her world was shattered by Ragnar’s infidelity with Aslaug.
His decision to bring Aslaug to Kattegat was a public humiliation that Lagertha’s pride could not endure.
She refused to be a second wife, choosing exile over a shared throne, and in doing so, established a core principle: she would not be subordinate.12
This path of self-reliance led her into a second marriage with Earl Sigvard of Hedeby.
This relationship was a crucible of suffering.
Sigvard was abusive, insecure, and constantly sought to diminish her.14
He ridiculed her warrior spirit and subjected her to physical and mental torment.16
Her eventual killing of Sigvard, aided by his nephew Einar, was an act of violent liberation.
When the people of Hedeby chose her as their new Earl, it was the ultimate vindication.
Hedeby became the symbol of her self-creation, proof that she could not only survive without Ragnar but thrive and rule in her own right.18
Therefore, when Kalf usurped her, he was attempting to negate this entire journey.
His justification that he had a “better claim” because he was born in Hedeby was a direct assault on the legitimacy she had earned through merit and conquest.9
It was an attempt to reduce her, once again, to an outsider with no inherent right to power, echoing the way Aslaug had displaced her in Kattegat.
He wasn’t just stealing her land; he was stealing her story.
The Vow as a Binding Contract
When Lagertha returned from the Paris raid and became Kalf’s lover, their relationship was established on a single, brutal condition.
She told him plainly that their intimacy was contingent on his acceptance of one fact: “she will one day kill him for having stolen her title from her”.18
Multiple sources confirm this vow was an explicit and accepted term of their affair.7
This was not an emotional threat made in a moment of passion.
In the world of Vikings, governed by oaths and honor, Lagertha was establishing a binding contract.
She was being transparent about the unchangeable reality of their situation: his betrayal had sealed his fate, and no amount of love or shared success could ever erase that debt.
By accepting her terms, Kalf willingly stepped into a tragedy of his own making.
He was blinded by his desire for her and fatally underestimated the depth of her resolve, believing, as actor Ben Robson noted, that they had “found a level playing ground” and that love could overcome the past.3
Ragnar’s subsequent refusal to intervene and help her reclaim Hedeby only solidified her position.12
He told Kalf it was a personal matter for the two of them to work out, effectively reinforcing that Lagertha alone was the arbiter of this justice.23
The vow was set in stone.
The only question was when and how it would be fulfilled.
Part II: The Damascus Steel Forging – An Analogy for a Warrior Queen
The central paradox of Lagertha’s actions can only be resolved by abandoning a binary view of her emotions.
She was not choosing between love and ambition.
Rather, these two opposing forces were being forged within her, creating a new, more complex and resilient psychological state.
The process is best understood through the analogy of Damascus steel.
This legendary material was renowned for its incredible strength and sharpness, characterized by the distinctive swirling patterns on its surface.
These patterns were the result of a process called forge welding, where layers of high-carbon steel (which is very hard but brittle) and low-carbon iron (which is soft and flexible) were repeatedly heated, hammered, and folded together.
The final blade was not a compromise; it was a synthesis.
It possessed the hard, sharp edge of the steel and the resilient, shatterproof flexibility of the iron.
Lagertha’s psyche, in the period leading up to Kalf’s death, was this forge.
The pressures of betrayal, love, survival, and rule were the hammer blows, fusing two contradictory aspects of her nature into a singular, formidable will.
The Hard Steel: Unyielding Ambition and a Warrior’s Honor
This is the high-carbon steel of Lagertha’s character—the core, unbendable element of her identity.
It is her absolute refusal to be diminished, controlled, or made subordinate to any man.
This trait was forged in the fires of her early life experiences.
She left Ragnar, the great love of her life, rather than accept the humiliation of sharing him with Aslaug.12
She later refused a proposal from the powerful King Ecbert, not out of dislike, but because she valued her status as an independent ruler more than the title of Queen consort.14
Her ambition is for sole, undisputed authority.
In the brutal patriarchal world of the Vikings, she understands that for a woman, shared power is temporary power, and dependency is a death sentence.18
This “hard steel” dictates that any existential threat to her autonomy and earned power—like Kalf’s usurpation—is an offense that cannot be forgiven.
It must be met with absolute resolution.
Her vow to kill him was not just a promise; it was an expression of this core principle.
To a person of honor, a word given is a debt that must be paid.
Breaking her vow would be tantamount to breaking herself.
The Soft Steel: Genuine Affection and the Ghost of a Future
This is the low-carbon iron—the more flexible, vulnerable, and human part of Lagertha.
It is her capacity for love, her desire for partnership, and her longing for a future that seemed lost to her.
Despite the unforgivable nature of his betrayal, the evidence strongly suggests her feelings for Kalf were not entirely a performance.
There were signs of an attraction even before he betrayed her.7
During the siege of Paris, he saved her life in a moment of chaos, an act that forged a genuine, if complicated, bond between them.3
Unlike her abusive second husband, Sigvard, Kalf seemed to genuinely admire her strength and desire her as an equal.24
Their final kiss, as he lay dying, is widely interpreted by viewers and critics as an expression of genuine, tragic affection—a final goodbye to what could have been.5
The pregnancy—whether real or a strategic lie—was the ultimate manifestation of this “soft steel.” The Seer had told her long ago that she would bear no more children, a prophecy that had caused her immense pain.7
The possibility of a child with Kalf represented a miraculous second chance at the family life she had lost.
It was the ghost of a future she desperately wanted, offered by the one man she was honor-bound to kill.
This internal conflict is what makes her story a tragedy, not just a revenge plot.
She was not immune to his charms or the future he offered; she was dangerously susceptible to them.
To clarify this internal war, we can lay out Kalf’s standing in a simple ledger.
| Credits (The Soft Steel – Reasons for Affection) | Debts (The Hard Steel – Reasons for Death) |
| Professed his love and desire for her 10 | Usurped her hard-won Earldom of Hedeby 14 |
| Saved her life during the raid on Paris 3 | Betrayed her trust after being her right-hand man 11 |
| Ruled with her as an equal (at least publicly) 3 | Plotted with Erlendur to assassinate her son, Bjorn 3 |
| Was overjoyed by the news of her pregnancy 1 | Undermined her legitimacy by claiming a “better right” 9 |
| Admired her strength, unlike her previous husband 14 | Forced her into a position of weakness, reliant on others (Ragnar) for aid 12 |
The Forge: The Wedding as Crucible
The wedding day was the crucible, the moment of ultimate heat and pressure where these two incompatible metals had to be permanently fused.
It was the point of no return.
To proceed with the marriage would have been an act of surrender.
It would have meant allowing the “soft steel” of her affection to compromise the “hard steel” of her identity.
By marrying Kalf, she would be publicly forgiving his unforgivable sin.
She would be breaking her solemn vow, thereby destroying her own honor.
She would be accepting a man who tried to erase her legacy as her equal and the father of her child.
It would have been a complete negation of the powerful, independent Earl Ingstad she had fought so hard to become.
Her ambition would be tempered, her authority shared, her very essence compromised.
The murder, at that precise moment, is the final, violent hammer blow of the forge.
It is the only act that resolves the paradox.
She takes the affection, the partnership, and the potential for a future (the soft steel) and folds it into her unyielding ambition and honor (the hard steel).
The act is not a choice between love and power; it is the tragic synthesis of them.
She emerges from the tent, not as Lagertha the wife or Lagertha the lover, but as Earl Ingstad—a singular, unified entity whose will has been proven absolute and whose strength is now legendary.
The love she felt for Kalf is not simply discarded; it is consumed by the fire, becoming part of the tragic pattern on the blade she has forged from her own soul.
Part III: Anatomy of a Killing – Addressing the Lingering Questions
Viewing the murder through the lens of the Damascus Steel analogy helps clarify the lingering questions that surround the event.
Each detail, from the plot against her son to the nature of her pregnancy, becomes a critical part of the forging process.
The Plot Against Bjorn
A crucial, complicating factor was Kalf’s conspiracy with Erlendur to have a berserker assassinate Bjorn in the wilderness.2
While the show leaves it ambiguous whether Lagertha knew the concrete details of this plot at the exact moment she killed Kalf, it serves as the ultimate retroactive justification for her actions.
Within the Damascus Steel framework, this plot is the final, decisive hammer blow that perfects the blade.
It transforms her act from one of personal honor and political ambition into one of supreme maternal protection.
It erases any lingering moral ambiguity for the audience.
Even if she acted solely to fulfill her vow and reclaim her power, we know her instincts were fundamentally correct.
Kalf was not just a political rival who had wronged her; he was a mortal threat to her only surviving child, her bloodline, and Ragnar’s legacy.
This knowledge hardens her resolve beyond question, proving that the “soft steel” of affection could never be allowed to protect a man who would harm her son.
The Pregnancy: Real or Ruse?
The question of whether Lagertha was truly pregnant or if it was a strategic lie is one of the most debated points among fans.
The Seer had prophesied that her womb was barren, a source of great sorrow for her.7
Yet, she announces the pregnancy to Kalf, whose ecstatic reaction and immediate marriage proposal set the final act in motion.1
The brilliance of the writing is that the story functions perfectly regardless of the truth.
- If the pregnancy was real: It represents the ultimate temptation of the “soft steel.” It was a miracle, a chance to have the one thing power could not give her. In this scenario, her choice becomes infinitely more tragic. She is forced to sacrifice not just a man she may have loved, but the impossible child she desperately wanted, all for the crown she knew she could not live without. It is the most profound testament to the unbendable nature of her “hard steel” core.
- If the pregnancy was a ruse: It stands as a masterclass in strategic manipulation, proving her ability to play the “long game” is every bit the equal of Ragnar’s.6 She identifies Kalf’s greatest weakness—his desire for a legitimate family with her—and uses it as bait to lure him into the perfect trap.5 By feigning the one thing that would make him drop his guard completely, she engineers the ideal moment to strike, ensuring his total emotional and physical vulnerability.
In either interpretation, the pregnancy is the catalyst.
It is the element that brings the heat in the forge to its highest temperature, forcing the final, irreversible fusion of her will.
The Final Kiss: Mockery, Pity, or Love?
The final kiss, shared as Kalf bleeds out in her arms, is the poignant and haunting conclusion to their story.
It is not an act of mockery or contempt.
It is a tragic acknowledgment of the “soft steel”—a final, intimate farewell to the genuine affection that existed between them and the potential future that was just extinguished in the forge.7
It is her goodbye to the man he could have been, and the life they might have had, if not for his original, foundational sin.
Kalf’s reaction is just as telling.
He accepts the kiss and his death with a kind of peaceful resignation.3
In that final moment, he seems to finally understand the woman he loved.
He remembers the vow he agreed to in Paris and accepts the consequences of the contract he signed in blood and desire.3
His death is not just a murder; it is the fulfillment of a promise.
The shared kiss is their mutual acknowledgment of this tragic, inescapable truth.
Conclusion: The Solitary Throne
The murder of Kalf on their wedding day stands as the most significant turning point in Lagertha’s character arc since she walked away from Ragnar.
It is the moment she fully and brutally actualized her own power, cementing her identity as a ruler beholden to no man.
It was an act not merely of destruction, but of creation.
In the blood of her lover and would-be husband, she forged herself anew, emerging as the sole, undisputed Earl of Hedeby—the queen she was always destined to be.
This triumph, however, came at a terrible price.
The act that secured her throne also cemented the tragic, solitary nature of her path.
By proving that she could not build a future even with a man for whom she held genuine affection, she effectively destined herself to a reign of isolation.
She had learned the hardest lesson of power: that love can be a vulnerability, and trust a fatal liability.
The strength of a Damascus steel blade comes from its fused, contradictory nature, but it is ultimately a weapon, designed for conflict, and it stands alone in the armory.
So too, did Earl Ingstad.
She had won her crown, but in doing so, ensured she would have to wear it alone.
Works cited
- Recap: Vikings 4.5 “Promised” – Sling Blog, accessed August 6, 2025, http://blog.sling.com.s3-website-us-east-1.amazonaws.com/whats-on/recap-vikings-45-promised
- Vikings Season Four Episode 5 Review and Recap! Promised! | Mike The Fanboy, accessed August 6, 2025, https://www.mikethefanboy.com/vikings-season-four-episode-5-review-and-recap-promised/
- Vikings shocker: A spoiler-y interview – Entertainment Weekly, accessed August 6, 2025, https://ew.com/article/2016/03/17/vikings-death-promised/
- Vikings: “Promised” Review | Den of Geek, accessed August 6, 2025, https://www.denofgeek.com/tv/vikings-promised-review/
- lagertha kills Kalf – bladeofthesashurai – WordPress.com, accessed August 6, 2025, https://bladeofthesashurai.wordpress.com/tag/lagertha-kills-kalf/
- ‘Vikings’ Season 4 Keeps Lagertha’s Bloody Promise – Inverse, accessed August 6, 2025, https://www.inverse.com/article/13054-vikings-season-4-keeps-lagertha-s-bloody-promise
- [Spoilers] Kalf and Lagertha : r/vikingstv – Reddit, accessed August 6, 2025, https://www.reddit.com/r/vikingstv/comments/4ayuc7/spoilers_kalf_and_lagertha/
- Vikings season 3 – Wikipedia, accessed August 6, 2025, https://en.wikipedia.org/wiki/Vikings_season_3
- ‘Vikings’ Season 3 Spoilers: Episode 5 Synopsis Released; What Will Happen In ‘The Usurper’? [VIDEOS] | IBTimes, accessed August 6, 2025, https://www.ibtimes.com/vikings-season-3-spoilers-episode-5-synopsis-released-what-will-happen-usurper-videos-1851692
- Vikings Season 3 New Clip From Episode 5 EARL KALF AND LAGERTHA HD – YouTube, accessed August 6, 2025, https://www.youtube.com/watch?v=LGXtfwhf2Jk
- Content That Contains Spoilers: Why did Lagertha kill Kalf in the …, accessed August 6, 2025, https://www.quora.com/Content-That-Contains-Spoilers-Why-did-Lagertha-kill-Kalf-in-the-Vikings-Did-she-know-that-Kalf-tried-to-kill-her-son
- Vikings: Ragnar & Lagertha’s Relationship Timeline, Season By Season – Screen Rant, accessed August 6, 2025, https://screenrant.com/vikings-ragnar-lagertha-relationship-timeline-each-season/
- Vikings: The 10 Worst Betrayals In the Series – Screen Rant, accessed August 6, 2025, https://screenrant.com/vikings-worst-betrayals/
- Vikings: Lagertha’s Lovers, Ranked By Likability – Screen Rant, accessed August 6, 2025, https://screenrant.com/vikings-lagertha-lovers-ranked-by-likability/
- Vikings: 10 Most Shameless Things Lagertha Ever Did – Screen Rant, accessed August 6, 2025, https://screenrant.com/vikings-lagertha-shameless-moments/
- Every Character Lagertha Dated Across Vikings Seasons 1-6 – Screen Rant, accessed August 6, 2025, https://screenrant.com/vikings-show-lagertha-characters-dated/
- Vikings – Review of Season 2 Episode 6: Unforgiven – Medievalists.net, accessed August 6, 2025, https://www.medievalists.net/2014/04/vikings-review-season-2-episode-6-unforgiven/
- [Spoilers] S03E08 Lagertha is a bitch : r/vikingstv – Reddit, accessed August 6, 2025, https://www.reddit.com/r/vikingstv/comments/328cpq/spoilers_s03e08_lagertha_is_a_bitch/
- [SPOILERS] The one thing that annoys me about this show. : r/vikingstv – Reddit, accessed August 6, 2025, https://www.reddit.com/r/vikingstv/comments/81tihd/spoilers_the_one_thing_that_annoys_me_about_this/
- Vikings season 4 shocker: Kalf pays price for ‘fatal attraction’ towards …, accessed August 6, 2025, https://www.ibtimes.co.uk/vikings-season-4-shocker-kalf-pays-price-fatal-attraction-towards-legartha-1550302
- [Spoilers] Not helping Lagertha retake her earldom was Ragnar’s worst moment – Reddit, accessed August 6, 2025, https://www.reddit.com/r/vikingstv/comments/1eqljd2/spoilers_not_helping_lagertha_retake_her_earldom/
- ‘Vikings’ recap: ‘The Usurper’ – Entertainment Weekly, accessed August 6, 2025, https://ew.com/recap/vikings-season-3-episode-5/
- Vikings: Lagertha, Kalf, and why is Hedeby so important? – Time Slips, accessed August 6, 2025, https://timeslipsblog.wordpress.com/2015/05/13/vikings-lagertha-kalf-and-why-is-hedeby-so-important/
- Vikings: Lagertha… a Warrior Goddess worth dying for! | Time Slips – WordPress.com, accessed August 6, 2025, https://timeslipsblog.wordpress.com/2015/04/16/vikings-lagertha-a-warrior-goddess-worth-dying-for/
- Vikings season 4 – Wikipedia, accessed August 6, 2025, https://en.wikipedia.org/wiki/Vikings_season_4
- The #ShieldGeeks Discuss #VIKINGS S4 Ep. 1 – Lissa Bryan, accessed August 6, 2025, https://www.lissabryan.com/2016/02/the-shieldgeeks-discuss-vikings-s4-ep-1.html
- Vikings Season 4, accessed August 6, 2025, https://funwithvikings.neocities.org/index_fourth_s
