10 Comic Book Catastrophes That Killed Millions
2. The Incursions - New Avengers
Death toll: Tens of billions
Still, it could be even worse than that. All of the X-Men could have been erased from existence, multiple times over, with increasing severity and an assured amount of pain.
Jonathan Hickman's superb run on the intertwining Avengers and New Avengers titles saw the team having to deal with a series of incursions, which sent the multiverse collapsing in on itself.
Thanks to some cosmic gubbins alternate Earths also started to crash into the main Marvel Universe, which threatened to spell the end of not only the main Marvel Universe, but all the multiverses in existence. As such, a secretive group of Avengers who call themselves the Illuminati had to figure out a way to stop this. Much to the chagrin of Captain America, Tony Stark and Reed Richards come up with a weapon to destroy those alternate Earths before they have a chance to end their own.
The group as a whole have wrestled with the moral implications of that, but it's not stopped them from ending literally dozens of realities. Heroes, one and all!