Blade's unexpected cameo in Eternals supports a theory from Avengers: Endgame that Marvel is setting up Britain's superhuman spy agency, MI-13. The Avengers have come to define the Marvel Cinematic Universe, but back in 2018 then Disney CEO Bob Iger noted there were plans to develop "what I'll call a new franchise beyond Avengers." That comment has naturally led to intense speculation, with attentive viewers looking for any hint of what this new franchise could be.

In the wake of Avengers: Endgame and Spider-Man: Far From Home, several pointed to the potential introduction of the British superhuman spy agency MI-13. Spider-Man: Far From Home saw Nick Fury and Maria Hill base themselves at the Shard, a building traditionally associated with MI-13 in the comics - and a natural base of operations for super-spies like Fury and Hill. Avengers: Endgame appeared to drop a Captain Britain Easter egg, with an explicit reference to "Braddock" -  a nod to the family who inherit the mantle of Captain Britain. What's more, the MCU's Phase 4 already features two MI-13 members, with Kit Harington playing Black Knight and Mahershala Ali playing Blade. The MCU really did seem to be setting up MI-13 - all that was needed was a way to tie Blade and Black Knight together.

Related: Eternals: Every MCU Easter Egg & Reference

Eternals' post-credits scene did just that, in a scene in which Dane Whitman claimed the Ebony Blade in the hopes of using is to rescue his beloved Sersi. An unseen voice - actually Mahershala Ali's Blade - interrupted, asking him if he was quite sure he was ready for this. It was only a voice cameo, because Marvel hadn't decided on Blade's costume at the time of shooting, but it wasn't a coincidence. According to Eternals producer Nate Moore [via the Phase Zero podcast], Marvel is strongly linking Blade and Black Knight. "The Ebony Blade, the characteristics of the Ebony Blade are not dissimilar to some degree of vampirism," he explained, "and we think that's an interesting kind of thing to play with. So we kind of knew that was on the table." It's difficult to say precisely how Blade and Black Knight are connected in the MCU, but the very fact they've been tied together makes MI-13 even more possible.

Captain Britain MI-13

MI-13 would be a very different superhero team to the Avengers. Although they include heavy-hitters such as Captain Britain, in truth they're a spy agency that operates in the shadows. That makes them better suited to intense espionage stories, or else supernatural adventures in which they face mystical threats. They've frequently gone up against vampires, and in fact Blade isn't the only vampire to have served on the team; the super-speedster Spitfire was bitten by a vampire, but remained an active hero in spite of the bloodlust. It's easy to see MI-13's story potential, especially given Marvel's past success with spy dramas such as Captain America: The Winter Soldier.

MI-13 has never had a major presence in the comics, but Marvel's long since proved they can take Z-list concepts and turn them into A-list stars. Their biggest comic book run spun out of the "Secret Invasion" comic book event, and Marvel Studios is bringing that to life in a Disney+ TV series starring Samuel L. Jackson's Nick Fury. Given Fury (or, rather, a Skrull impersonating him) was already based at MI-13's headquarters in Spider-Man: Far From Home, it's quite possible the MCU will imitate the comics and further set up MI-13 in Secret Invasion. The potential is clear, and hopefully it will soon be realized. Either way, Blade's presence in Eternals lends weight to the long-theorized Endgame set-up.

More: Eternals Shows How MCU Phase 4 Can Solve Its Character Problem

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