King Arthur: Legend of the Sword (2017) DVD

Mordred, an iron-fisted warlock, and his armies lay siege to Camelot, seeking to establish the dominance of magic-wielding mages over humankind. Uther Pendragon, king of the Britons, infiltrates Mordred's lair and beheads him, saving Camelot. Uther's treacherous brother Vortigern, who covets the throne, orchestrates a coup and sacrifices his wife Elsa to moat hags to become a demon knight, who kills Uther's wife and slays him in combat. The only survivor is Uther's son, who drifts away in a boat and ends up in Londinium, where he is found and raised by prostitutes.

Arthur grows into a skilled fighter and man of the streets. Arthur and his friends confront a group of Vikings who had mistreated one of the prostitutes, forcing him to pay her restitution. Afterwards, the brothel is raided by the Blacklegs, Vortigern's minions, and Arthur learns that the Vikings were under the king's protection. Arthur tries to escape the city but is caught and put on a ship with hundreds of other men; the Blacklegs have been forcing all men of Arthur's age to try to pull a sword that has appeared near the castle from the surrounding stone. Arthur is able to remove the sword but is quickly overwhelmed by its power and passes out. Vortigern meets with him in the dungeon, revealing his true lineage.

Meanwhile, a mage identifying herself as an acolyte of Merlin presents herself to Uther's former general, Sir Bedivere. At Arthur's planned execution, the mage uses her magic to stage a diversion while Bedivere's men rescue Arthur. Taken to Bedivere's hideout, Arthur initially refuses to help them. The mage persuades Bedivere to take Arthur to a realm called the "Darklands," where he's given a vision of how Uther sacrificed himself to save Arthur and entomb the sword in stone. Arthur learns Vortigern was responsible for persuading Mordred to rebel against humanity, and he returns determined to destroy Vortigern.

With his friends and Bedivere's men, Arthur stages a series of ambushes against Vortigern, culminating in an assassination attempt in Londinium. The rebels sense a trap but attack anyway, fleeing to a fighters' school run by Arthur's mentor George, where they are overrun by the Blacklegs. Seeing the mage held at knifepoint, Arthur unleashes Excalibur's potential, single-handedly killing all of the soldiers. The rebels are able to escape the city except for Arthur's injured friend Back Lack, who is killed at Vortigern's hand in front of his son Blue.

Ashamed of his failures, Arthur tries to throw away the sword, but the Lady of the Lake returns it and shows him a vision of England's future under Vortigern's rule. Coming to terms with his responsibility, Arthur reunites with Bedivere. When they return to the rebel hideout, however, they discover all of their allies dead, Vortigern having found them and delivered an ultimatum: if Arthur does not surrender himself, the captured mage and Blue will die.

Arthur surrenders himself, but as Vortigern is about to execute his nephew, a giant snake summoned by the mage attacks and devours Vortigern's men. While Bedivere and the others lead an attack on the castle, a desperate Vortigern sacrifices his only daughter and is transformed into the demon knight, confronting Arthur in a separate dimension. Despite his fighting skill, Arthur is beaten, and he is about to submit when he witnesses a vision of his father, convincing him to accept the sword and his character as his own. Arthur violently slays Vortigern but blesses him as he dies.

In the aftermath, Arthur dissolves Vortigern's pact with the Vikings and begins building a Round Table where his knighted friends will meet. Blue and the prostitutes arrive with the crown of Uther, which Arthur accepts, holding the sword aloft.