His Mage

Both Arthur, rightful heir of the throne of Camelot, and Excalibur have been missing since the night Camelot burned and the King was murdered. For two decades the brother of the King, Vortigern, has ruled through fear; torturing and persecuting his own people in his quest to command the power of the missing sword.

A mysterious woman known only as The Mage comes to Camelot set on overthrowing the tyrannical rule of King Vortigern that has driven her people into hiding. In order to restore the throne, the sword Excalibur must be found and pulled from stone by the Born King. When she finds him however, Arthur knows nothing of his Royal birth nor the magical sword he inherited from his father nor does he have any interest in either. In order to defeat Vortigern, The Mage must not only convince Arthur to accept his destiny but, perhaps even more impossibly, trust her.

King Arthur: Legend of the Sword Fanfic
Arthur x The Mage