Arthur and his knights ride to the stone where Excalibur is embedded in the stone, only to find Sir Kay is already there. Kay attempts to remove the sword from the stone and declare himself the king of Camelot, however while doing so, he turns to dust. After witnessing this, Arthur steps forward and succeeds in claiming Excalibur, only to find that the end of the legendary sword is missing. Arthur tells his knights that the important thing is he is king. However, Arthur becomes determined to reattach the tip - which is actually the Dark One's Dagger - back to Excalibur to make it whole again. Neglecting his wife Guinevere and his royal duties, Guinevere and Lancelot venture out to collect the dagger, but end up settling for magical sand from Avalon which can give something the illusion of being fixed. Arthur learns of this deception, and uses the sand on Guinevere so she thinks their marriage is fixed, before using the sand to turn Camelot into a grand kingdom befitting a noble, heroic king.
When Emma Swan, along with some of her family and friends arrive back in the Enchanted Forest, King Arthur and some of his knights ride out to meet them. Arthur claims that Merlin prophecized their arrival before the sorcerer vanished, and they all arrive in Camelot. Snow White and David Nolan learn of Arthur's unsavory plans, although Arthur uses the Avalon sand on them, which silences their suspicions until Merlin is freed. Arthur forms an alliance with Zelena, who tethers Merlin to Excalibur, forcing Merlin under Arthur's control. Eventually, their plans fail which forces Arthur and Zelena to travel to DunBroch, Merida's kingdom, in search for a magical helm that Arthur attempted to take from Merida's father. Merida learns that Arthur was responsible for her father's death and vows vengeance after Arthur and Zelena flee DunBroch empty-handed. After Hook unleashes the fourth Dark Curse, they are all taken to Storybrooke where Arthur believes there is no way back to Camelot, and so he intends on making Storybrooke the new Camelot. However, the Charmings discover that Arthur is up to no good and lock him up at the police station. Arthur eventually escapes, but is killed by Hades. In the Underworld, Arthur helps Hook retrieve the storybook pages for Emma, but decides not to go to Olympus. Arthur eventually overthrows the Underworld's ruler Cruella De Vil and reigns over the Underworld for fifty years.
- Guinevere Pendragon (widow)
- S5, E01: "The Dark Swan"
- S5, E02: "The Price"
- S5, E03: "Siege Perilous"
- S5, E04: "The Broken Kingdom" (flashback)
- S5, E05: "Dreamcatcher"
- S5, E06: "The Bear and the Bow"
- S5, E07: "Nimue" (flashback)
- S5, E08: "Birth"
- S5, E09: "The Bear King" (flashback)
- S5, E10: "Broken Heart" (flashback)
- S5, E21: "Last Rites"