Supervillains aren't a cute and cuddly bunch. They're out to do evil, and with that evil often comes a high body count. While some supervillains in the Marvel universe are content to commit homicide on a local scale, others have far loftier and more outrageous ambitions. When the dust settles, the streets flow red, and the bodies are piled high— much to their delight.
There are Marvel baddies who have engaged in mass homicide so egregious that it borders on unfathomable. How some of these characters manage to sleep at night is a mystery with all the corpses they've left in their villainous wakes.
10 The Void
The Void is the dark half of Robert Reynolds, the Superman-esque superhero known as Sentry. In his latter form, he's one of the most powerful superheroes in the Marvel universe. When Void takes over, things go bad, and fast. This alternate identity assumes itself when Sentry falls victim to his own psychological disturbances.
Void's worst display of mass homicide occurred when he slaughtered over one million people living in Manhattan. The event was so catastrophic that he called on Doctor Strange and Reed Richards to help make Earth's populace forget Sentry's existence altogether, thereby nullifying his Void counterpart.
9 Magneto
While Magneto has been shown to be just as great a superhero as he is a notorious villain, his latter actions define his character. His disregard for non-mutant lives is legendary at this point, and he's shown little reluctance or hesitation to put that viewpoint on full display.
The most egregious example of this occurred when he used a massive electro-magnetic pulse to knock out Earth's technology. Though the act itself was not homicidal, the fallout would have been catastrophic. Planes would have fallen out of the sky, hospital equipment would have ceased to function, and grocery stores would have run out of food in a matter of days. The death toll from this event must have been catastrophic.
8 The Red Skull
The villainous Red Skull has had quite a lot of time to perfect the killing arts. He cut his teeth as a high ranking Nazi operative during WWII, carrying out the Third Reich's ambitions. When the war ended, the Skull didn't stop his campaign of terror, but rather broadened its scope and impact.
His most horrible act of mass murder took place when he commandeered Genosha, and set up a mutant concentration camp. No explanation is needed as to what happened next: With the power of Charles Xavier at his control, the Skull proved almost completely unstoppable. He also once saved Adolf Hitler from an assassination attempt, which puts a bunch more murders on his hands by proxy.
7 The Sentinels
While the Sentinels themselves are a creation of the human known as Bolivar Trask, they've racked up a considerable kill count over the years. Their goal to destroy mutant-kind has proved to be an effective campaign, regardless of whether they're acting independently, or under the influence of villains like Cassandra Nova.
It's estimated that the Sentinels have wiped out over 16 to 17 million beings across the world, many of them mutants but not exclusively. This is one horrific body count that rivals the worst mass murdering regimes in human history, which is a testament to Trask's megalomania.
6 Ultron
The villainous Ultron has done some heinous things during his time, including the annihilation of Slorenia, the assimilation of an entire planet using a techno-organic virus, and threatening to blow Earth up five times over with a series of tactical nuclear strikes. One event stands above the rest, however.
After assimilating his creator Hank Pym, Ultron spread a variant of his virus across multiple alien worlds, effectively slaughtering their inhabitants in the process. Under this guise, Ultron believed that the inhabitants posed a threat to the galaxy, and needed to be taken out.
5 Apocalypse
The super-mutant Apocalypse lives by a twisted and incorrect take on Darwin's "survival of the fittest" formula, but he doesn't care. He's willing to extinguish any life form who he perceives as weak and not fit to continue on. He ended up getting his wish during the Age of Apocalypse story arc, albeit by mistake.
After a freak mistake caused Professor Charles Xavier to be erased from history, Apocalypse managed to rise up and take over the entire planet. He then waged a genocidal campaign to wipe out humanity so that mutants could ascend as the dominant life form on the planet. It was one of the most homicidal rampages of any Marvel supervillain ever.
4 Dark Phoenix
The Dark Phoenix first displayed its power when it took over the form of the mutant Jean Grey. Already a powerful telepath and telekinetic, the pairing was as perfect as it was terrifying. The Phoenix put its powers on full display when it engaged in genocide of billions of alien beings on a distant planet.
It all started when the Phoenix absorbed the energy from a nearby star. The resulting collapse of the star triggered a supernova which obliterated the D'Bari species in the blink of an eye. Though Jean Grey could not be blamed, such a realization would have been devastating for anyone to cope with.
3 Galactus
Galactus has existed before the creation of the known universe, which is a testament to his innate power. He views lesser life forms (basically everyone) as inferior and not worth his consideration; a fact he uses to justify his ravenous hunger and the destruction of countless worlds to feed it.
It's impossible to tell just how many worlds have fallen to Galactus' hunger, but it's certainly far more rather than less. Entire civilizations and ecosystems have been wiped out in the blink of an eye as Galactus travels from world to world, seeking to sustain himself. He's an apex predator with the appetite of a teenager.
2 Thanos
Thanos literally worships Death incarnate, and that can never bode well for the inhabitants of a universe. Insane, power-drunk and enormously powerful, Thanos has proven himself to be one of the most lethal threats in the Marvel comic book universe, with few notable exceptions.
His most infamous act of mass murder occurred when he gained control of the Infinity Gems and used his powerful Infinity Gauntlet to wipe out half the universe's inhabitants with a snap of his fingers. His reason was as simple as it was terrifying— to show off to his lady mistress Death, who was none-too impressed by his behavior.
1 Doctor Doom
Many Marvel fans might think Thanos holds the crown as the most homicidal supervillain, but that dubious pseudo-honor actually goes to none other than Victor Von Doom. His egotistical drive to become master of the known universe is unparalleled among villains, a fact which ended up bringing him nothing but emptiness when he achieved said goal.
Doom's penchant for uber-mass murder is notorious. He once used the Ultimate Nullifier to lay waste to an alternate universe, and he used the power of the Beyonders to wipe out untold numbers of universes in one fell swoop, while crowning himself God Emperor. His own justifications for this act are morally murky, but there's no denying the unrivaled body count.