Heading into Eternals, we expected to see at least something from Thanos, but it's his brother - Harry Styles' Starfox - who makes his Marvel Cinematic Universe debut in the movie's mid-credits scene. Both characters have a long, complicated history with the Eternals in the comic books; however, both on the page and screen, their father is the Eternal A'lars.
While he brought a perfect son into the world in the form of Eros, Thanos was essentially considered a Deviant. Horrified by his appearance and sensing the darkness with him, Thanos' mother immediately tried to kill her son after first laying eyes upon him. After that, the boy who'd one day be known as the Mad Titan quickly embraced the bloodlust he felt as a child.
We all know what happened next, of course, but in the MCU, it sounds like Starfox could have been a major contributing factor to Thanos becoming a tyrant who wiped out half the universe.
Writer Kaz Firpo tells Screen Rant: "I think, for the sake of this movie as a film, we really just decided to tell this story, and maybe when we get out into the cosmos you might...I mean, we're literally meeting Thanos' actual brother at the end of the film, and I think there's room for Eros - well, Harry [Styles] - to have a conversation about that."
"I think that Starfox is a lot responsible for why Thanos is the way he is, to have that...all jokes aside, to have this perfect brother who can make anyone fall in love with him? It does something to you. So I hope we get to see a little bit more of that in Number 2."
Starfox certainly doesn't appear to have an issue with being introduced as Thanos' brother by Pip the Troll, so exploring what their relationship looked like promises to be undeniably fascinating. There were once plans to flash-back to the villain's childhood in Avengers: Infinity War, but that could easily be revisited as we start learning more about Eros' place in this shared world.
Eternals is now playing in theaters. Click here to check out our look at what it sets up for the future.