King Arthur

King Arthur is the king of Camelot who was prophesied by Merlin to pull the magical sword Excalibur from its stone and rule the kingdom. However, prophesies don't always turn out as planned and Arthur discovers that the tip of the sword is missing, so he and his most trusted knights decide to keep it a secret and start a quest to find the missing half.

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 favourite 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.

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 Exalibur 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.

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 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.

Gallery
Gallery of photographic stills released to promote the character.