Excalibur is basically the most famous sword in human history. Everybody knows the deal: pull it from a stone, become a king, get a round table. But the ABC show Once Upon a Time decided that wasn't complicated enough. They turned the legend of Once Upon a Time Excalibur into a multi-season, dimension-hopping headache that connects to the Dark One, the Holy Grail, and a guy named Merlin who spent a few centuries as a tree.
It’s a lot.
If you're rewatching the show or just trying to figure out why the sword looks like a broken jigsaw puzzle for half the series, you’ve come to the right place. The show didn't just adapt Arthurian legend; it basically took a blender to it.
The Origin Story Nobody Expected
In the world of Once Upon a Time, Excalibur wasn't just forged by some lady in a lake. Well, sort of, but the "how" is way more magical.
Everything starts with the Holy Grail. Thousands of years before Emma Swan ever set foot in Storybrooke, a soldier named Merlin and his buddy were wandering the desert. They found the Grail. Merlin drank from it, got magic, and eventually realized that the world needed a way to tether the darkness that keeps popping up.
He didn't just make a sword. He made a tool.
Merlin used a flame from Prometheus—yes, they mixed Greek mythology in there too—to forge the Grail into a sword. That sword was Excalibur. It was designed to be the ultimate weapon, something that could cut through anything, including the darkness itself. But here's the kicker: it wasn't meant to be whole for very long.
To control the darkness of the "Dark One," Merlin had to split the sword. He snapped off the tip. That small, jagged piece of metal became the Dark One’s Dagger. If you’ve watched the show, you know that dagger is the most dangerous 10 inches of steel in existence.
So, whenever you see the Once Upon a Time Excalibur in its "incomplete" form, you're looking at a weapon that is literally missing its soul—or at least its darker half.
Why Arthur Was Actually a Villain
Most versions of King Arthur make him out to be this golden boy. Not here.
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In Once Upon a Time, Arthur is obsessed. He’s a guy who grew up being told he’d be the savior of Camelot, but when he finally pulled the sword from the stone, it was broken. Imagine the disappointment. You do the impossible task, you prove your worth, and the prize is a jagged piece of metal that looks like a manufacturing error.
Arthur spent his entire life trying to "fix" the Once Upon a Time Excalibur. He became a bit of a tyrant because of it. He lied to his people. He used a magical dust to make his kingdom look perfect while it was actually falling apart.
He needed the Dagger.
The middle of Season 5 is basically a high-stakes scavenger hunt. Arthur wants the Dagger to reunite it with the sword because he believes a "whole" Excalibur will give him the power to destroy the Dark One and make Camelot the greatest kingdom ever. The problem is that the sword doesn't want to be fixed. It represents a balance between light and dark that isn't supposed to be messed with.
The Connection to Emma Swan and the Dark One
This is where things get truly messy.
In the fifth season, Emma Swan becomes the Dark One. She’s the "Dark Swan." She ends up in Camelot with the rest of the Storybrooke gang, and they’re all trying to find a way to get the darkness out of her without killing her.
The Once Upon a Time Excalibur is the key.
Because the sword and the dagger were originally the same object, they have a "magnetic" pull toward each other. Emma eventually realizes that if she can mend the sword, she can use it to "cut away" the darkness forever. But magic always has a price. It’s the show’s favorite catchphrase for a reason.
To fix the sword, you need the blood of someone who has been "touched" by both light and dark. You need a specific kind of spark. It’s not as simple as a blacksmith and an anvil. When the sword is finally made whole again, it doesn't just look like a regular broadsword. It glows with an eerie, flickering light that signifies it’s back to its original, god-like state.
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The Visual Evolution of the Blade
The prop team for Once Upon a Time actually did a pretty cool job with the visual storytelling here.
- The Broken Blade: When Arthur has it, the sword has a flat, blunt end. It looks truncated. It’s a symbol of his incomplete reign and his personal failings.
- The Dagger: Short, wavy, and inscribed with the name of the current Dark One (Zoso, then Rumplestiltskin, then Emma). It’s purely functional and purely evil.
- The Reforged Excalibur: When the two pieces are joined, the name of the Dark One disappears from the blade. It becomes a unified weapon.
Interestingly, the sword's design changed slightly throughout the seasons. If you look closely at the hilt in the early cameos versus the Season 5 spotlight, there are minor differences in the filigree. That’s just the nature of long-running TV production, but fans love to debate if it means there were "multiple" swords across different timelines. (Spoiler: Probably not, just different props).
Common Misconceptions About the Sword
A lot of people think the Once Upon a Time Excalibur is just a regular sword that can kill the Dark One. It's not.
Actually, it’s much worse.
If the Dark One is killed with the Dagger, the killer becomes the new Dark One. We see this happen over and over. But if the Dark One is killed with the reforged Excalibur, the darkness is extinguished entirely. The power dies with the person.
This is why Rumplestiltskin (Mr. Gold) is so terrified of it. He doesn't want to die, but more importantly, he doesn't want to lose his power. The sword represents the end of an era. It represents the end of the "game" he’s been playing for centuries.
Another weird detail: The sword has a "protection" spell on it. In the show, Merlin mentions that only the "worthy" can pull it, but "worthy" in Camelot usually means "whoever Merlin says so." In Once Upon a Time, it’s less about being a good person and more about having a specific destiny tied to the prophecy.
The Legacy of the Blade in Storybrooke
By the time the show wrapped up, the Arthurian arc was mostly settled, but the sword’s impact lingered. It redefined what "The Dark One" actually was. It turned a simple monster-of-the-week concept into a cosmic tragedy about a broken tool.
Honestly, the show's handling of Excalibur is one of its most ambitious swings. They took a legend that has been told a thousand times—from T.H. White to Disney’s The Sword in the Stone—and managed to make it fit into a world where Snow White carries a bow and Rumplestiltskin owns a pawn shop.
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It wasn't always perfect. Some of the CGI in Camelot was... let's say "of its time." And the logic of how the sword gets moved back and forth between worlds can get a little dizzying if you try to map it out on a timeline. But the core idea—that the world's most famous sword is just the "light" half of a cursed dagger—is a stroke of writing genius.
Actionable Insights for Fans and Writers
If you’re a writer looking at how Once Upon a Time handled this, or just a fan trying to make sense of the lore, here are a few takeaways on why this worked (and what to watch for):
Look for the visual cues.
The show uses the state of the sword to reflect the state of the characters. Arthur’s broken sword reflects his broken morality. Emma’s struggle to fix the sword reflects her struggle to fix her own soul. When you're watching, don't just look at the action; look at the object.
Understand the "Price of Magic."
Every time the Once Upon a Time Excalibur is used, someone loses. To forge it, Merlin lost his mortality. To fix it, Arthur lost his mind. To use it, Emma almost lost her life. In this universe, powerful objects aren't gifts; they're burdens.
The Multi-Myth Connection.
If you're confused about the lore, remember that the show creators (Adam Horowitz and Edward Kitsis) loved "mashing up" stories. Excalibur isn't just British folklore here; it's a mix of:
- Christian mythology (The Grail)
- Greek mythology (Prometheus's Flame)
- Original show lore (The Dark One)
Rewatch Season 5 with "The Dagger" in mind.
If you go back and watch the Camelot episodes, pay attention to how characters react when they see the sword and the dagger in the same room. The tension isn't just about the characters; it's about the two pieces of a "god-killing" puzzle finally coming together.
The story of the sword in Once Upon a Time is ultimately a story about choice. The sword can be a tool for protection, or a weapon of mass destruction. It all depends on who is holding the hilt.
If you're diving back into the series, keep an eye on the transition between the "middle-age" flashbacks and the "modern" Storybrooke scenes. The way the sword travels through time is a masterclass in how to keep a magical MacGuffin relevant for over 20 episodes of television. Just don't expect it to follow the history books—this is Camelot by way of Disney, and it's much more complicated than the stories your teacher told you.