According to the comic book legend, a young Thanos could appear in The Eternals. This is far from confirmed, and it seems like Jim Starlin himself isn’t sure exactly where he got that news from. But it’s an exciting concept, and one that doesn’t seem completely out of question. After all, The Eternals will cover a ton of time and ground, with a story that spans thousands of years. So a quick appearance by Thanos doesn’t seem totally out of the question.