10 Comic Villains With The Highest Body Count
6. Dark Phoenix
Death Toll: Billions of Aliens (An Entire Planet)
Typically, Jean Grey is a good person and one of the most important people on the X-Men's roster, but there have been times in her past when she became something else. Due to Jean's immense psychic power, she has attracted the attention of a cosmic being known as the Phoenix Force, which resulted in some serious repercussions for a lot of people.
On its own, the Phoenix Force is neither good nor evil, but due to its governing of all life and rebirth, things can get messy when it possesses a powerful being like Jean. When it happened the first time during the Dark Phoenix Saga in 1980, a lot of people died all over the universe.
She ended up turning on her team, which caused her to flee to another galaxy. The trip left her a bit tired so she consumed the energy of the D'Bari star, which resulted in a massive supernova.
That act led to the destruction of the only civilized planet in the system, killing billions of sentient beings. She was declared to be an evil more serious than Galactus and was sentenced to death by the Kree, Skrull, and other galactic empires, but ultimately sacrificed herself at the end of the story... only to return (and die again) pretty much every other decade.