The Ebony Blade may be the key to understanding Black Knight's role in Marvel's Phase 4 movie The Eternals. In 2020, the classic Avenger will finally join the MCU, but how the character fits into the upcoming superhero epic hasn't been revealed.

Confirmed at SDCC 2019, Eternals is the second film on Marvel Studios' slate for Phase 4. Directed by Chloe Zhao, Eternals is expected to release in November of 2020. The movie, which centers on a race of super-powered aliens created by the Celestials, will explore the history of the MCU. Eternals stars Angelina Jolie as Thena, Salma Hayek as Ajak, Richard Madden as Ikaris, Lauren Ridloff as Makkari, and more.

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Perhaps the most interesting addition to the cast is Game of Thrones star Kit Harington as Black Knight. Unlike Ikaris, Thena, and the others, Black Knight isn't an Eternal. In the comics, Dane Whitman is a skilled swordsman and a key member of the Avengers. The character had an important role in several Avengers stories during the late 1980s and early 1990s. As Black Knight's ties to the Avengers strengthened, he served as the face of the team, appearing on the front cover of numerous Avengers comics, often taking more of the spotlight than Captain America. For a while, Black Knight even led the team. He has had a prolific history in Marvel Comics that involves the Avengers, MI-13, the Heroes for Hire, and Doctor Strange. But what does any of this have to do with the Eternals?

Black Knight Doesn't Fit Into The Eternals Movie

Black Knight Dane Whitman

Dane Whitman is the only confirmed human character in Eternals. In a cast of god-like immortals, Black Knight certainly stands out. For every other character in Eternals who has been officially announced, there aren't any questions as to why they're in the movie, because they're important characters in Eternals comics. The only exception is Black Knight, who isn't a major player in any of their biggest stories.

His only connection is his relationship with Sersi, which is a storyline that played out in the pages of The Avengers. At this time, Black Knight was in love with the Inhuman, Crystal. Their will-they-won't-they relationship became complicated when Sersi developed feelings for Black Knight. When Sersi became infected with an Eternals disease which causes mental instability, the Eternals arrived and decided that the only way to save her was to create a physic bond between her and the object of her affection, Black Knight. Though Dane wasn't happy about the arrangement, he didn't have much of a choice. Unfortunately, the bond caused a strain on Black Knight's mind. Since their bond didn't completely fix the problem with Sersi, the two were forced to leave the universe. Later, the bond was severed and both characters moved on.

This is the extent of Black Knight's connection to the Eternals. Since Sersi does appear in the movie, played by Gemma Chan, Eternals could explore their relationship, but it seems unlikely that Marvel is adding its greatest swordsman to the MCU just to give one of the Eternals a love interest.

Related: Black Knight Could Be Very Important To Avengers 5

Black Knight's Ebony Blade Can Be His Eternals Connection

Black Knight with his sword in Marvel

At the heart of so many of Black Knight's stories in Marvel Comics is the Ebony Blade. Forged centuries ago from a meteor and enchanted by Merlin himself, the Ebony Blade has been passed down from generation to generation, eventually falling into the hands of Dane Whitman. As a magical weapon that can cut through anything, the Ebony Blade has seen Black Knight through several major events in the comics.

Despite its many uses, Black Knight has put it aside in the past, and for good reason. The sword comes with a blood curse that was created from all the people killed by the sword's original owner, Sir Percy of Scandia. When someone spills blood with the sword, the blood curse takes a toll on the wielder's psyche, and compels him to commit even more acts of violence. What it does to those who shed innocent blood is profoundly worse. The blood curse has ruined the lives of several of Black Knight's ancestors. Dane is well aware of what it can to do people - and himself. Black Knight knows that each time he uses the sword, he loses a piece of himself in the process. Fighting the curse has been a never-ending struggle for the character.

The Ebony Blade's importance to Black Knight makes it the most obvious aspect of the character that will be explored in Eternals, perhaps even more so than his relationship with Sersi. The history of the Ebony Blade could be what brings Black Knight into the story. It's possible that Eternals will rewrite the sword's origin story and make it an Eternals artifact. In the comics, it goes all the way back to the Arthurian era, and in the MCU it could go back even further. Marvel's Eternals is expected to span a thousand years, so the movie could introduce different characters who have wielded the weapon.

Why Phastos Should Make The Ebony Blade

Phastos Eternals

The Eternals in Marvel Comics possess advanced technology and superior weaponry, so it makes sense that a weapon as powerful as the Ebony Blade could have come from them. But which Eternal could have built the sword? For anyone familiar with the comic book characters, the obvious answer is Phastos (Brian Tyree Henry). Most of the Eternals' weapons and technology was invented by Phastos, who is their engineer and blacksmith. Phastos also forged the sword of Kingo Sunen (Kumail Nanjiani's character in Eternals). Phastos' craftmanship is so exceptional that Kingo's sword can cut through nearly any material.

Related: Every MCU Character Confirmed For Phase 4

With this level of skill, it doesn't seem far-fetched at all that Phastos could have forged it thousands of years ago. In the modern era, it could belong to Kit Harington's Black Knight, who may become curious about where the sword came from, especially if he wants to remove the curse. If Dane researches the sword, he may even succeed in tracing it back to Phastos, and in turn, the Eternals. In the MCU's The Eternals, the Ebony Blade can provide a bridge between the characters.

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