With Eternals, the MCU moves to a more cosmic focus, away from just Thanos and onto a new set of galactic weirdos, including the Celestials.
But in the Marvel comics, Thanos and the Eternals have a strong connection that may chart a new course for the next phase of the Marvel movies. After an Eternals post-credits scene silently invoked the connection, let’s talk about how Thanos ties into Phase 4, even after his story seemingly ended.
[Ed. note: This piece contains spoilers for Marvel’s Eternals.]
Thanos’ Eternals lineage
In the comics, Thanos is an Eternal, and one from a very important bloodline: His father, Al’ars, was the son of Kronos, who ruled the Eternals of Earth following a civil war that divided the original colony. Following his father’s death, Al’ars traveled the universe as the Mentor.
This took him to Titan, the moon of Saturn, and its own group of Eternals. There, he found the entire planet had been decimated in its own Eternal civil war with one survivor — the Titan Eternal Sui-san. Using a genetic device, the two rebuilt Titan and repopulated it with new Eternal-like beings dubbed Titans; they were stronger and could live longer than the original Titan Eternals, but were still outclassed by the Earth Eternals.
Eventually, Sui-San and Al’ars had two children of their own: Eros (we’ll get to him) and Thanos.
Not an Eternal, not yet a Deviant
Thanos is an Eternal, yes, but he’s also a Deviant. Why? Because genetics!
See, Eternals and Deviants are made from the same batch, and that means there’s eventually some crossover. An Eternal getting a Deviant-like mutation was later dubbed “Deviant Syndrome,” or the way Thanos looks with his purple skin and ridged chin. (Of the two sons, he’s the only one with this condition; Eros looks like a regular Eternal, something that Thanos naturally hated his brother for.) And because the Deviants’ evilness is tied to their biology (yikes), Thanos’ appearance freaked out Sui-san so much that when she first laid eyes on him after giving birth, she went mad and tried to kill him (also yikes!).
In the current Eternals run from Kieron Gillen and Esad Ribić, the genius Phastos discovered that Thanos is actually a “true Eternal,” same as the rest of them. It isn’t clear what this means for the character going forward; the next arc of Gillen and Ribić’s run will continue Thanos’ story, where he will be known as “Eternal Prime.”
Let’s talk about Eros
Created by Jim Starlin and first appearing in 1973’s Invincible Iron Man #55, Eros is Thanos’ younger brother. With good looks and the power of controlling other people’s emotions, Eros is both the superhero called Starfox and a massive fuckboi. If he wasn’t helping the Avengers with a crisis, he was being hedonistic as hell in space.
Like many fictional brothers, the two do not like each other, and Thanos will often just capture and torment Eros. They do get along, sometimes: They once had to work together to defeat Thanos’ future self, and they have a truce to meet once a year and bring each other gifts.
What’s this mean for the MCU?
Eternals’ first post credits scene shows Thena, Makkari, and Druig on their ship just as they realize that Sersi, Phastos, Kingo, and Sprite have been taken by the Celestial Arishem. Before they can formulate a plan, they’re interrupted by none other than Eros, played by Harry Styles. Introduced explicitly as Thanos’ brother by his sidekick Pip (Patton Oswalt), Eros offers to help the Eternals save their friends. And his fuckboi nature seems to be intact, as his introduction is set to “Feels Like the First Time” and he flirts with Thena.
Since the film ends with the standard “Eternals will return …” promise, Eros is probably included in that now, too. Should this movie succeed, it’s possible that Styles is locked in for an Eternals 2, and maybe even his own movie or show. (Surely his absence from the whole Infinity Saga is substantial enough for either.) How he connects to the Celestials and his overall purpose in the MCU remains to be seen, as is whether or not Thanos will pop up again for another Marvel sibling spat. Either way, the Eternals have themselves a new ally against the Celestials. One who will undoubtedly end up causing some trouble for them.