With the trailer for Avengers: Endgame finally here, Marvel Cinematic Universe fans have been poring over every detail in an attempt to figure out what the remaining heroes will face when the film hits theaters next year. That naturally leads to some serious theories and, one of them, points to the idea that it's not Thanos or even his devastating snap that is the real threat at the heart of Endgame. It's Death herself.
The idea of Lady Death having a role in either Avengers: Infinity War or Endgame isn't exactly a new one. From the time fans were introduced to Hela (Cate Blanchett) in Thor: Ragnarok, many assumed that Thor's brutal half-sister would play a big role with some assuming that Hela was herself Lady Death. As a refresher, in comics Lady Death is all but the imaginary girlfriend of Thanos who refuses to hand over her love to him despite his constant wishes. He lives to serve her, killing relentlessly in an effort to appease her thirst.
However, with Hela defeated at the end of Ragnarok it seems unlikely that she'd be returning to bring about an ultimate threat for the heroes -- though it's not impossible she could return. So, if not Hela as the embodiment of death, who? That's where a fan theory on Reddit comes in.
The theory from "Reinheart123" suggests that the "greater threat" the heroes face is Death herself -- Hela's mother. As the theory notes, Thor refers to Hela very specifically as his half-sister in Infinity War. As fans have learned, paying attention to even tiny details like that could reveal major information about the story so, by extrapolation, it could be Lady Death who is the true villain of Endgame. The theory goes so far as to suggest that Katherine Langford might even be playing the character as her casting is still rather mysterious. While that may or may not line up with the theory -- if Lady Death was, in fact, Hela's mother, Langford might be too young for the role -- the idea of Lady Death being the "big bad" of Endgame is an interesting one.
It also might be a bit of a stretch. While in comics Thanos is motivated to snap his fingers by his desire to woo Death, Infinity War completely divorced the Mad Titan from any romantic motives. Instead, the MCU's Thanos is driven by creating his sense of balance in the universe, albeit in the most horrific way possible.
Whatever the "greater threat" the heroes face in Avengers: Endgame, fans will find out for sure when the film opens in theaters April 26, 2019.