Warning: contains spoilers for Kang the Conqueror #4!
Marvel is subtly adjusting its lore to create new links between Kang, Black Knight, and the X-Men. Strangely, the diverse characters are connected by the mythical King Arthur - an individual who has always had connections to the Black Knight, but was recently redefined as a major enemy of mutantkind and one of the most hated conquests of Kang.
The Kang the Conqueror miniseries has focused on a younger version of the time-traveling villain, 31st-century teenager Nathaniel Richards, who desperately tries to escape his fate of becoming the infamous Avengers nemesis Kang. After encountering a Knight of Khonshu named Ravonna in ancient Egypt, Nathaniel becomes convinced that his salvation depends on winning the love of this woman and rescuing her from death at the hands of Pharaoh Rama-Tut, another variant of Kang. After assassinating a future version of himself, Nathaniel returns to Egypt to take Rama-Tut’s place and save Ravonna, but is unable to win her love. Fleeing to a war-torn future, Nathaniel encounters another incarnation of Ravonna, who he discovers is equally resistant to his affections. Heartbroken, Richards decides he will harden his heart through conquest, finally taking on the mantle of Kang the Conqueror.
In Kang the Conqueror #4 (from Jackson Lanzing, Collin Kelly, and Carlos Magno) after spreading his reign across the war-torn Earth of the future, Kang forges a time ship and decides to spread his conquest across time and space. Here Marvel hints at a subtle connection between Kang, Black Knight, and the X-Men with the conqueror beginning his campaign in Camelot. Kang reflects that he “ground the kings of the past to dust. Arthur most of all.” Kang has a long history with Camelot, besting Arthur in 1965's Strange Tales #134, but he does so as part of a larger plan, and actually spares Arthur's life and allows him to go free. In Kang the Conqueror #4, he expresses far more vitriol towards the king, who was recently revealed to be the ancestor of both current versions of the Black Knight - Dane Whitman and Jackie Chopra.
The recent Black Knight: Curse of the Ebony Blade (by Si Spurrier and Sergio Davila) confirmed that Jacks and Dane are descended from Arthur, with the implication that the first Black Knight, Sir Percy of Scandia, was his illegitimate son. This link is likely to be key to the upcoming Death of Doctor Strange: X-Men/Black Knight #1 crossover from Spurrier and Bob Quinn. King Arthur’s son Mordred, a bitter adversary of the Black Knight, was confirmed to be a mutant in Tini Howard and Marcus To's Excalibur #23. There, it was revealed that Arthur cast out his son for being a mutant, with the monarch currently warring on mutantkind in the mystical realm of Otherworld.
Arthur has generally been depicted as a hero in Marvel Comics, but there's been a definite move lately to cast him as a bigoted, anti-mutant villain. Recent mentions have strengthened his relevance to the Black Knight's origin, made him an active threat to mutants, and confirmed him as a particularly disliked enemy of Kang, weaving the three formerly unrelated (at least in the context of a shared universe) properties together through their Arthurian connection.
One reason for this odd decision may be that there are plans to link these characters in the MCU. Both Dane Whitman and a version of Kang were introduced into the MCU this year in Eternals and Loki respectively, and fan anticipated is high for mutants to be added to the movie universe. To see if the subtle connection between Kang, the X-Men, and Black Knight are movie related or if King Arthur is being established as a new comic big-bad, readers will have to check out Death of Doctor Strange: X-Men/Black Knight #1 and Kang the Conqueror #5 this December.