Warning! SPOILERS for Eternals
Although existence of the MCU's Deviants or the presence of Tiamut inside the Earth's core.
Now that Arishem has revealed himself to the world, anybody from the Avengers to SWORD to the Guardians of the Galaxy to what remains of the Nova Corps will probably start asking questions. The concept of an unborn Celestial poking through the Earth is sure to have ripples all across the universe in Phase 4 and beyond, and several characters may cross paths for the first time because of it. Not only that but the introduction of Black Knight also opens a whole new corner of the Marvel Cinematic Universe.
With Ajak dead, Ikaris burning in the sun, and the remaining Eternals divided, an Eternals sequel may not be coming anytime soon. However, that doesn't mean that the MCU will ignore these godlike characters and the repercussions of their mission. In fact, the seeds for many future MCU titles have been planted in Eternals.
Black Knight
The most evident setup for a future MCU property in Eternals is the introduction of Kit Harington's Dane Whitman, aka Black Knight. First presented as Sersi's boyfriend, Dane Whitman seems like a regular human who's accidentally involved in the affairs of ancient gods. However, Eternals teases Dane's complicated family history and reveals that he's in possession of the legendary Ebony Blade. Sersi's disappearance at the hands of Arishem has motivated Dane Whitman to pick up the cursed sword and take on the mantle of his ancestors to become the modern-day Black Knight.
Even more surprising than the appearance of the cursed Ebony Blade is the voice that stops Dane Whitman from touching it: Mahershala Ali's Blade. Black Knight and Blade aren't exactly known for working together. However, given their inclination for the mystical and their obsession for swords (voluntary or otherwise), it's easy to see why Blade would want to instruct Dane Whitman in the world of the occult. The most direct follow-up to Eternals could be a Black Knight movie or Disney+ show, which could explore the previous owners of the moniker, while it develops Dane Whitman's first steps as the cursed hero.
Blade
Blade has been a highly anticipated addition to the MCU since his movie was announced at San Diego Comic-Con 2019, where it was also confirmed that it won't arrive until Phase 5. Mahershala Ali's voice cameo in Eternals' post-credits scene marks the first appearance of Eric Brooks himself in the MCU.
The Latin inscription on the box where the Ebony Blade is stored reads “Mors Mihi Lucrum,” which means "Death is My Reward." This ominous phrase not only describes the dangers of the Ebony Blade and the curse of the Black Knights, but also seems to allude to the undead. It would be an understatement to say that Blade, the vampiric Daywalker, is well-versed in vampire matters. Blade could appear alongside Dane Whitman in a Black Knight movie or TV show prior to his own movie, though it's also possible that Dane Whitman appears as a ing character in Phase 5's Blade.
Black Panther 2
More than a decade after Iron Man 2's post-credits nod at Atlantis with SHIELD's tab on the Atlantean Ocean, Eternals finally gives Atlantis a reason to come in with the surface world. Tiamut's colossal frozen body will definitely take more than the entire workforce of Damage Control to clean up, which means that it may be up for the Atlanteans to do it. The Atlantean king Namor the Submariner, a powerful Marvel hero known for his bad temper, may believe that he's entitled to hold the surface world able for any damage caused to his kingdom.
Given that Namor is rumored to be Celestials' retaliation against the Deviants caused Atlantis to sink, so it's likely that an eventual Namor the Submariner movie will explore the influence the Celestials had on their kingdom.
Fantastic Four
Marvel's First Family has some strong foundations for their MCU introduction. Loki introduced He Who Remains, the benevolent variant of Nathaniel Richards, who's a descendant of Mr. Fantastic and the Invisible Woman. Eternals doesn't hint at the existence of Reed Richards, Ben Grimm, or Sue and Johnny Storm. Instead, it establishes the limitless power of the Celestials. This opens the door for another godlike entity setting his eyes on the Earth — just like every planet provides the Celestials with enough energy to induce their birth, every planet possesses the necessary energy to feed Galactus, the Devourer of Worlds.
Galactus is one of the Fantastic Four's most famous villains and one of Marvel's most powerful characters. If he notices Tiamut's failed birth and Fantastic Four movie could reveal that these bonds are one and the same, and perhaps Phase 4's Fantastic Four will lead to a Silver Surfer spinoff.
Guardians of the Galaxy Vol. 3
The Guardians of the Galaxy Vol. 3.
Infinity Watch
With Starfox and Pip the Troll introduced in Eternals' after-credits scene and Adam Warlock soon to be introduced in Guardians of the Galaxy Vol. 3, the chances of seeing a live-action Infinity Watch assembling for the first time are increasingly stronger. The Infinity Watch is a group of powerful cosmic characters who agree to protect every Infinity Stone to prevent a villain like Thanos from assembling another Infinity Gauntlet. The Infinity Watch doesn't have a regular lineup as fixed as the Avengers, but some of the team's most important are set to be key players in Phase 4.
The first version of the group was led by Adam Warlock and included Drax, Gamora, Maxam, Drax's daughter Moondragon, a reformed Thanos, and Pip the Troll — the latter of which was in charge of the Space Stone. Since Thanos is gone and Doctor Strange seems to be once again in possession of the Time Stone in Spider-Man: No Way Home, the MCU's Infinity Watch could draw inspiration from the second iteration of the team, which had Doctor Strange as the leader and had Captain Marvel and Star-Lord as new . It's also worthwhile to mention the Infinity Watch's third lineup, which had Loki as the leader and guardian of the Soul Stone, as well as Kang the Conqueror as the keeper of the Reality Stone and Ms. Marvel as the keeper of the Mind Stone. The biggest question regarding an Infinity Watch movie or Disney+ show would be how the Infinity Stones could return given that Phase 4 is distancing the MCU away from the cosmic McGuffins. Whatever the case, an Infinity Watch movie could be the first MCU installment to feature Thena, Makkari, Druig, Kingo, Phastos, and Sersi after the events of Eternals.
