The Legend of Prince Valiant season with the potential to become a major antagonist, is forgotten about until the very end of the second season. The characters of King Arthur, Queen Guinevere, Merlin, Sir Gawain, Sir Mordred, Lady Morgana, and Sir Kay are all major characters with origins in Arthurian legend. Also pulled from traditional lore are Camelot, the Knights of the Round Table, and Arthur's sword Excalibur. The general chivalric principles Camelot is famous for have been codified on this series as the New Order. In addition, the second-season episode "The Black Rose" features the characters of King Lot, King Uther, and Queen Igraine
King Arthur: Legend of the Sword Bros. made multiple attempts to make a new film based on Arthurian legend: one was a remake of "Excalibur", helmed by Bryan Singer, while the other was a film titled "Arthur & Lancelot", which would have starred Kit Harington and Joel Kinnaman in the title roles respectively. Warner Bros. worried that neither names were big enough, and attempted to replace both actors with more profitable ones, before eventually dropping the project altogether. Warner's next attempt to create a new King Arthur film was an attempt to create an Arthurian cinematic universe which would span six films, following different characters before