How Powerful Is Marvel's Death?
Death is one of the oldest cosmic beings in Marvel Comics and as threatening a force as the name implies. Having come into existence during the Big Bang, the abstract entity has since served as the guardian of mortality throughout the universe. Simply put, Death — usually personified as Lady Death or Mistress Death — is responsible for ensuring all life eventually ends.
As such, Death can control the cycles of life and death across the entire galaxy. On a whim, she is able to kill on a cosmic scale or even resurrect if she changes her mind. Since her debut in 1973, Death has been portrayed as seemingly immortal, omniscient, and omnipotent. It's her responsibility to maintain a balance in the universe, and she will continue to exist as long as life in the universe does. Life can't exist without death, and it falls on her to keep that equilibrium in place.
But despite the inherently fatal nature of the character and the terrifying amount of power she possesses, Death isn't necessarily a Marvel villain. But it's not just her control over mortality that gives her power.
A fate worse than Death?
Thanks to her unspeakably deadly powers, Death has caught the attention of some of Marvel's heaviest hitters. Most notably, she was the comic book inspiration for Thanos' quest to collect the Infinity Stones. While the Thanos we see in the Marvel Cinematic Universe wants to erase half of life after seeing his planet die from a lack of resources, in the comics, it's mostly because he has a crush on Death. After sensing an imbalance in the universe, Death exploits the Mad Titan's infatuation with her to help restore order. This eventually leads to his infamous snap, which is largely done in an (unsuccessful) effort to win her favor.
Whether she's doing the dirty work herself or having someone else do it on her behalf, Death's power is almost incalculable. Beyond her intrinsic control over the notion of life itself, Marvel's Death has proven that she can use simple guile to manipulate others into doing her bidding, even villains as formidable as Thanos. She doesn't even need to lift a finger to have half the universe wiped out.