The Eternals [1]' gorgeous cast is stacked [2], and for a split second in the latest trailer [3], we get a sneak peek of Kit Harington [4]'s character. That's right — Game of Thrones [5]'s Jon Snow is in the upcoming Chloé Zhao-directed Marvel project, and he'll be portraying the mysterious Black Knight. If you're wondering who this character is in the comics, we've got you covered with all the details that you need to know about him.

Let's get one thing out of the way: The Black Knight isn't an Eternal [6] — he's essentially a human superhero with a fancy sword. In the comics, the original Black Knight is Sir Percy of Scandia, a master of swordsmanship in the time of Camelot. Harington's iteration of the Black Knight is Percy's descendant, Dane Whitman, and he's the nephew of the villainous Nathan Garrett, who was fatally injured in a battle with Iron Man [7]. Dane assumes his uncle's Black Knight legacy, wielding the mystical Ebony Blade [8] after the spirit of Sir Percy contacts him. He later works with the Avengers, who find him useful for his deep scientific knowledge but don't fully trust him because of their past with his uncle Nathan. You could say that the Ebony Blade is, metaphorically speaking, something of a double-edged sword. While it has powerful mystic properties, it's also cursed in a way that makes its wielder more violent and bloodthirsty.

So, how does the Black Knight connect to the Eternals? At one point in time, Dane was in a love triangle with the Inhuman Crystal and the Eternal Sersi [9]. We briefly see Gemma Chan's Sersi with Harington's Black Knight, but the teaser focuses more on the relationship between Sersi and Richard Madden's Ikaris. Could we see a love triangle between the Black Knight, Sersi, and Ikaris? It's possible. It's also possible that we'll see the Black Knight's backstory get altered in the MCU so that he'll have somewhat a stronger connection with the mysterious Eternals. Given his extensive history in the comics, we wouldn't be surprised to see Harington in other Phase Four films [10] to come!