This article contains spoilers for Black Knight: Curse of the Ebony Blade #4.
Marvel Comics seems to be replacing the new Black Knight ahead of his MCU debut in Eternals. The first Black Knight was created by Stan Lee and artist Joe Maneely back in 1955, in a sword-and-sorcery comic set in the days of Camelot and King Arthur. That means the Black Knight is older than Marvel Comics itself - and Kit Harington will be playing the best-known Black Knight, Dane Whitman, in the upcoming Marvel blockbuster Eternals.
Marvel Comics is retconning the Black Knight ahead of his MCU debut, revealing the true nature of his cursed Ebony Blade - and that a Black Knight is even able to beat Thor in battle. Si Spurrier and Sergio Davila's current Black Knight: Curse of the Ebony Blade miniseries has further introduced a character named Jacks, who's served as something of a sidekick to Dane Whitman. Professor Jacks is an academic, working to become a full-fledged doctor of Arthurian mythology, who's dedicated her professional career to proving Camelot never existed. Jacks has learned she's a whole new type of sorceress - one who touches blood and can receive visions of the distant past, referred to as a "Time Seer." Now, though, it looks as though she's about to become part of the legends of the Black Knight herself.
Black Knight: Curse of the Ebony Blade #4 sees Jacks confront Mordred, the ancient illegitimate heir of Arthur who has been killing Arthurian historians. The murderer explains the killings were done because he needed to cut off the bloodline of Arthur, to ensure he was the only one left. "The line I belong to has become rather thin over the years," Mordred explains, "Nonetheless, Camelot has a way of... bubbling up. All those mythographers and historians... The very last of my distant relatives, dumbly reacting to the Old Magic in their blood. Building their careers and obsession around an ancient dream without knowing why." Significantly, though, the issue hints Mordred has made a mistake - for Jacks fits the bill as an Arthurian scholar, in one scene Dane Whitman discovers that there's a secret around her, and the cover of the next issue shows her wielding the Ebony Blade herself.
Mordred has followed the male line in identifying potential rivals, and that makes sense, but magical curses don't necessarily care whether you are male or female. Given that is the case, there could be countless other men and women descended from the blood of King Arthur, and thus capable of wielding the Ebony Blade. The Black Knight has always been something of a legacy title, passed from one generation to the next, and it looks as though Jacks will be the next one to bear this title.
Marvel typically attempts to establish a sense of synergy between their comics and the MCU, but in this case, they're diverging instead. The MCU is about to introduce Dane Whitman, just as the comics move away from him, giving him a different role; the story in Black Knight: Curse of the Ebony Blade #4 ends with Whitman apparently dying, but the cover of the fifth issue shows him wearing the Ebony Crown and very much alive, with Jacks bearing the Ebony Blade. It will be fascinating to see this new Black Knight in action.