King Arthur

King Arthur is a supporting character on Once Upon a Time. Since he was a little boy, Arthur was prophesied to pull Excalibur from its stone and become King of Camelot. However, due to the elusive nature of the prophecies he was given, he had no idea that the sword would be as broken as the kingdom he was supposed to rule it with - and his marriage to the lovely Queen Guinevere grew just as splintered as he made it his life's goal to find Excalibur's missing end, known as the Dark One's dagger. Eventually, he turned to magic to solve his problems, making his adulterous Queen bend to his will and his kingdom's humble tower appear as a grand palace. With his life having been ruined by the thankless tasks he was assigned, he makes it his new mission to complete the sword and use it to run through the person who foresaw he would draw it in the first place: Merlin.

Before the Curse
As children, a romance blossoms between Arthur and Guinevere. While walking through the village of Camelot, Arthur tells her about his dreams of Camelot becoming a great kingdom with him as their king. After promising that they're not only dreams, he reveals a secret about a powerful sorcerer who is trapped inside a tree. He tells her about the night the sorcerer spoke to him and prophesied that he'd one day pull a sword from a stone, making him king, and promises to make Guinevere his queen. He promises to fill the kingdom with her favorite flowers, middlemists, on her birthday and then takes her to a meadow of the flower. However, they come across a sword stuck in some stones and Kay approaches from behind. The older boy tells Arthur he'll never be king and Camelot will remain a broken kingdom. Arthur wonders if Kay is right, but Guinevere assure him that he'll find the sword as long as he follows his heart.

Arthur, and his two most trusted knight friends, Lancelot and Percival, travel on horseback to find a location given in a prophecy by Merlin, where Excalibur awaits in a stone. Once they arrive they discover another knight, Kay, has already beaten them to the sword. Arthur warns Kay that the sword isn't his to take, but the knight mocks Arthur and the prophecy which states Arthur will be king. After revealing he wants to be king, Kay attempts to pull Excalibur from the stone. However, it kills him, turning him into a pile of dust. He is shocked at the sight of seeing a man turn into a dust. After Lancelot claims that he's next, Arthur bravely steps forward for his turn at pulling the sword. He is successful...except for the fact that the tip of the sword is missing. Fearing that the people won't accept Arthur as their king, the three knights decide to lie about the broken sword, deciding to start a new quest to find Excalibur's missing half.

After returning to the village with Excalibur, Arthur proves himself to it's people and shows the sword, hiding the broken tip. He takes Guinevere aside and confesses the truth, claiming the sword must be made whole. A while later, during his reign, Arthur becomes consumed in his quest and begins neglecting Guinevere. On her birthday, she tries to get him to dance with her, but he researches instead, leaving her waiting. She soon realizes Arthur didn't plan the celebration, but Lancelot. As she and Lancelot dance, Arthur approaches them and reveals he's discovered the missing tip to Excalibur, the dagger. After Arthur leaves, Guinevere uses a gauntlet that points to Arthur's greatest weakness, which at that time is the dagger. After realizing Arthur is going in the wrong direction, she and Lancelot set off to find the dagger. When Arthur returns empty handed, he spots Guinevere and Lancelot having a romantic farewell, so he later confronts her. She tells him they found the dagger, so he desperately searches her things. Finding nothing, he demands to know where it is, but she shows him a vial of enchanted sand that can "fix" anything. He becomes angry as she was going to trick him into thinking the sword is complete, but she argues that she wanted his love again, but now she realizes she desires something else. A paranoid Arthur tosses some of the sand on Guinevere, making her believe she loves him. He then disperses more sand from Merlin's tower, which magically transforms Camelot into a castle kingdom.

Season 2
During his quest for Excalibur's missing half, King Arthur leads his men to the kingdom that lies north of Camelot, DunBroch. Known to be a magical land, he hopes on finding magic that will help him retrieve what he wants. The clans of DunBroch, which are led by King Fergus, await the invasion and prepare for war. A battle between the two kingdoms takes place, with Arthur and Fergus both fighting in the war. Despite Merida trying to stop Arthur by firing an arrow at him, Fergus is slain. Arthur takes Fergus' helm, believe it to be an enchanted helm which can magically lead all mean into a battle for him. However, he soon realises that the helm doesn't work, for when he tries it, nothing happens. He and his army are surpassed and they end up loosing the battle.

Season 5
As the residents of Storybrooke stand beside Granny's Diner in the woods, which they used to travel to the Enchanted Forest, King Arthur and his knights, including Percival, arrive on their horses. Protecting her friends from potential danger, Emma asks who they are, so Arthur introduces himself and explains that they've come to find them. A confused Hook asks what he means, so Percival tells Arthur they think their arrival a surprise. Snow asks if he was expecting them, so Arthur explains that Merlin their arrival a long time ago. Emma questions where the wizard is for she was told that he's missing and Arthur confirms that he has been for years, but not for much longer, because according to the prophecy, they're destined to reunite them with Merlin. The king then escorts the group back to Camelot, taking them all inside the castle where they're welcome by trumpets.

Before the Third Curse
After entering the castle, King Arthur introduces his guests to Guinevere before announcing that a ball will be held in their honor. After Hook asks about Merlin, Arthur takes them to a tree in the courtyard, which the wizard is trapped inside; Charming reveals they need Merlin to defeat the Dark One. When Arthur asks whom the prophesied savior is, Regina lies and claims it to be her. During the ball, Arthur and Guinevere dance among everyone else, however, things suddenly take a tragic turn when Percival is killed by Charming for attacking Regina and Robin. In the aftermath, Regina confesses to being the Evil Queen, but Arthur tells her Camelot is a place of second chances and he believes that her healing Robin's wounds is a sign she is the savior (although he's unaware Emma used dark magic). Later that night, Arthur sits at the Round Table with Percival's shield when Guinevere enters, claiming their guests frighten her. She expresses fear over the future since Merlin tells that what happens in prophesies, but not how they happen. Arthur tells her to see it through since the newcomers want to destroy the Dark One, and that'll help him obtain the dagger which he can finally unite with Excalibur. He explains that if Excalibur is not made whole then they'll lose the kingdom they worked so hard to build. As a show of acceptance of what they must do, Guinevere places her hand over Excalibur, while Arthur puts his hand over hers.

In Merlin's tower, Mary Margaret, Emma, Regina and Belle work to try and find a way to free the Sorcerer from the tree he's trapped in; it is soon decided that they need a way to communicate with him in order to learn more about his condition, and to do that they're going to need a certain magical toadstool known as the Crimson Crown, found in the Forest of Eternal Night. David offers to find it for them, and Arthur offers to go with him, first stopping by the Round Table to collect a chest of valuable items to help them on their way. While there, David is told of Siege Perilous, a seat at the Round Table reserved for the most pure-hearted of knights, formerly taken up by the now deceased Lancelot. The two of them bond on their quest over things such as their wives and their similar humble beginnings, before making it to the toadstool... which is across a bog, and the only way over it is a weak bridge. David carefully goes over it, suspecting that it will only take one, and successfully gets the toadstool; however, he is then attacked by undead knights who drag him underwater. Arthur rescues his new comrade, but the Crimson Crown is lost. Due to the valor expressed by David on this quest, Arthur knights him into the Knights of the Round Table, allowing him to sit down on siege perilous. David is honored, and his friends and family are extremely proud of him. However, Arthur secretly meets with Guinevere afterwards and reveals he stole the toadstool off of David, for he doesn't want them using it.

Trusting the newly knighted David, Arthur reveals the truth about Excalibur's missing half. He asks for David's assistance with finding the Dark One's dagger, which will allow him to purge the Darkness for good. David leaves to think, and when he arrives, he confesses that Emma is the Dark One. Arthur is sympathetic to the situation and agrees to help rid Emma of the Darkness. David then reveals that Lancelot is alive and Guinevere overhears this, demanding to know his whereabouts. Arthur fears the dagger isn't safe now that Lancelot is back, but when David opens the box to show the dagger, they realize it is missing and Snow must have taken it. While David searches for her, Arthur follows Snow and Lancelot into the Vault of the Dark One where they prepare to hide the dagger. Arthur forces Snow to give him the dagger, but when he attempts to summon Emma, Snow reveals the dagger is fake. David then appears behind Arthur, revealing he and his wife conspired against him. A handcuffed Arthur is led to the diner by the trio who plan on uniting Excalibur with the dagger and making Guinevere the ruler of Camelot. However, Guinevere ambushes them with the Knights of the Round Table, frees Arthur, and orders Lancelot's imprisonment. After taking Excalibur back, Guinevere uses the Sands of Avalon on Snow and David to gain their compliance in getting the real dagger.

King Arthur gathers some of his soldiers and confronts Regina and Emma Swan at the Merlin tree in the courtyard, where the women are in the middle of concocting a potion that will be able to free the sorcerer. He demands they give him the dagger, but Regina chooses not to obey the king and gives Emma the last ingredient to finish off the potion. Arthur and his men attack, but Regina defends herself and shoots magical fireballs at them. After the potion is complete, a stream of light and dark magic is activated, allowing Emma to harness it and use it to revert the tree back into Merlin in his human form. The sorcerer immediately confronts Arthur about what a disappointment he turned out to be, but Arthur rages about the sorcerer giving him false prophecies that ruined his life. The king goes to unsheathe Excalibur, but Merlin bluntly points out that they both know the sword in its incomplete form is useless against him. Arthur warns that things are not over yet before he and his men retreat.

After the heroes free Merlin, Lancelot and Merida from the castles prison, Arthur makes a cauldron potion to destroy them for conspiring against him. When his guards arrive, he instructs them to arm all sides of the castle. He takes one of the guard's helms and demonstrates what his potion can do, melting it into nothingness. He orders his guards to take the cauldron and throw it on any of the intruders. Later, at the Round Table, Arthur prepares Excalibur and a spell book, but the heroes enter to apprehend him. Regina uses magic to freeze him, but Zelena soon reveals herself as Arthur's accomplice, bringing with her a captive Snow. Zelena unfreezes Arthur and casts a spell to tether Merlin to Excalibur, giving Arthur the power to control and summon him. Arthur confronts Merlin for making him into the man he is today because of false prophecies and a broken sword. The sorcerer offers to help unite the sword and dagger, but Arthur believes there's no going back and claims to not want Merlin to have all the glory. Merlin is disappointed that Arthur now only cares about glory, but the king stops the conversation and orders the sorcerer to disarm the heroes and send them away. ("Nimue")

King Arthur controls Merlin into visiting Emma at the diner to deliver an ultimatum; hand over the Flame of Prometheus or her family will be killed. Emma arrives in the Caledonian Forest, to find her family and friends tied to trees with Arthur, Zelena and Merlin guarding over them. She asks for them to be released before she gives the flame, but when Zelena threatens to start killing people, she forfeits the flame in a box. Arthur asks the witch to check if it's real, but when she opens it, coils of dark magic wrap around her and pin her against a tree. Arthur thus commands Merlin to attack Emma and choke Snow. However, Merlin is briefly able to resist Arthur's control and Snow is released. Arthur continues to command the sorcerer to kill, but Hook manages to break free from his bond and he punches the king in the face, causing him to cut him on the neck with Excalibur. Hook disarms Arthur and stops him from grabbing the sword, so the king rushes to free Zelena, who teleports him with her to the castle.

After safely returning to the castle, Arthur manages to convince Zelena that they both still need each other before revealing they need to visit DunBroch in order to collect an enchanted helm that will help get his knights on his side in the battle against Merlin and Emma. They visit the witch's cottage, where Arthur has a quick run in with Red Riding Hood in her wolf form before she's put to sleep by Zelena, and then they talk to the witch, who explains she gave the helm to King Fergus in a deal. The duo track down Merida and take her bow, which belonged to her father, and use it to locate the missing helm. After finding the helm in a river, Merida confronts Arthur for killing her father and stealing his helm during the southern invasion. Arthur admits he did, but that the helm he took wasn't magical, meaning King Fergus didn't use magic to lead men into the battle and win the war. Merida duels Arthur to stop him getting the real helm, and after the United Clans show up as backup, Arthur finds himself defeated yet again, so he quickly retreats with Zelena.

Season 5
Shortly after arriving in Storybrooke, Arthur and his knights ride through the streets and spot Grumpy and Happy. They disarm the dwarfs and demand to know where they are. A while later at the mayor's office, Regina explains that the memory loss and world transportation is part of a curse. Charming confesses that they were dishonest about the Dark One and Snow White reveals that the Dark One is their daughter Emma and that she cast the curse. Robin soon enters and notifies the group that other people from Camelot have been found in the woods, so Arthur goes with Charming to search for them. After everyone is found, supplies are distributed to the visitors and tents are set up for shelter. As Arthur sets up his tent, Guinevere finds him and notices that Excalibur is missing from his scabbard. David assures that couple that they'll find the sword if it's in this world. A Fury soon appears and kidnaps Robin because of an unpaid price of magic. Regina becomes injured while trying to rescue him, leaving Arthur, Charming, Snow and Grumpy to track it down. By night time, when the fury summons a ferryman to the Underworld, everyone intervenes as the creature drains Robin's life away. They all link hands and Fury attempts to drain their lives, but they become too powerful and the Fury's power explodes on itself.

As he doesn't trust the Storybrooke folk for lying about Emma being the Dark One, Arthur plans on making the town the new Camelot for his people, all the while gaining David's trust. As part of the plan, he tells his squire, Grif, to steal from a relic chest. Arthur lies to David about someone taking a bean which could take his people home, so David examines the chest which was broken in to. He asks Grif for any theories on who did it, and without the sheriff noticing, Arthur gives Grif a knowing look, to which the squire talks about Emma being the culprit. David thinks it's possible since she just stole an axe, but Arthur points out that she wouldn't need magic and the chest has scratch marks on it. At the pawnshop, they ask Belle if anyone pawned in a magic bean, but she answers negatively. David improvises and takes an ordinary cup and announces to the people of Camelot that they must drink from it to find the thief. Grif flees on horseback, causing Arthur and David to follow him in the latter's truck. Arthur takes over the wheel while David knocks the squire off his horse jousting style. Grif "confesses" to stealing the chest, claiming he was sick of the way Arthur treated him, but claims there was never a bean. David privately asks Arthur if he thinks Grif is lying, but he says he believes him. David promises to find another way home and then prepares to lock Grif up when they discover a toadstool - the Crimson Crown - that came from Camelot during the curse. Later, Arthur visits Grif in his cell and convinces him to ingest a fatal poison for the good of Camelot, so the townspeople will never learn the truth of what happened.

Grif's disappearance is soon made known to the others and as they wonder how he was able to get away, Arthur deducts that he must have been lying about not having the magic bean and used it to return to Camelot alone. Guinevere is angry that he could've been so selfish and then grows concerned over how this development will affect their people's spirits. Snow offers to host something for them and Henry suggests a dance. As they all leave the sheriff's station, Belle runs up to them and reveals that Rumple is missing. Later that night, during the party that has been thrown for Camelot's people, Hook and his allies reveal to Arthur that they found Excalibur hidden under Emma's house in her basement. After some questioning, Arthur confesses that he knows the Dark One's dagger is the missing half to Excalibur, and that if the sword is made whole again by uniting them, the combined weapon would be capable of extinguishing the darkness, but in the Dark One's hands, could also be used to snuff out the light.

Regina reveals that Emma was successful in freeing Merlin in Camelot, to the surprise of David and the others. The question is raised of why he didn't remove the darkness from her, and Regina proposes that they find out by communicating with him, having figured out a spell that will allow them to do so using the Crimson Crown. A cauldron is prepared down in Regina's vault, and all that's needed to reach the Sorcerer is for one of his "chosen" to drop the Crimson Crown into it; they summon Arthur, who suggests that he do it alone since no one else has ever been around when he received Merlin's prophecies in the past. Not wanting to take any risks, David and the others give him his privacy... only for him to throw the magical toadstool onto the fire beneath the cauldron, clearly not wanting the heroes to contact Merlin. This is deduced when the Crimson Crown is found merely charred - for magical toadstools don't burn - and Regina realizes that there's one other person in town who was chosen by Merlin: the Author. As such, they have Henry drop the toadstool into the cauldron and a message from Merlin appears, suggesting that Emma did something awful to him during the missing six weeks; they are told that their best hope lies with Nimue.

Arthur is in his tent enjoying a candlelit evening with Guinevere when David enters to confront him about his attempt to destroy the Crimson Crown. He reveals the spell still worked and questions the king about Nimue, someone Merlin mentioned who can defeat the Dark One. The couple remain silent and Guinevere stands up, staring at her husband. As David waits for an answer, Arthur flips the table and cuts a hole in the tent, escaping through it with his sword. He flees into the woods with Hook chasing him. The king trips over a tree trunk, but when Hook hovers near him, he trips the pirate to the floor and holds him at sword point. However, before he can finish him off, Emma magically appears and blocks his sword with the complete Excalibur. Arthur is shocked to see his sword finally reunited before Emma uses her magic to throw him against a tree, knocking him out. Arthur is imprisoned in the sheriff's station and Hook tries to force the truth out of him about Camelot. When it's made clear he doesn't know what happened, David makes the pirate back off, claiming Arthur is a king without a kingdom who has little importance now.

Gallery
Gallery of photographic stills released to promote the character.