The Eternals explain why they didn't stop Thanos from wiping out half the universe in new trailer
In a voiceover, we learned that though the Eternals have watched the humans complete their little tasks and go about their daily little lives for centuries, they have never interfered. But now, those humans want some answers.
“Why didn’t you guys help fight Thanos or any other war? All of the terrible things throughout history?” Kit Harington’s character Dane asks Sersi (Gemma Chan). When a visibly stricken Sersi tells him that they were instructed never to meddle, it doesn’t really look like it’s a good enough answer for Dane.