10 X-Men Villains With The Biggest Body Counts
2. Dark Phoenix
When Jean Grey was dying in space, she came into contact with a cosmic entity called The Phoenix Force. After this godlike bird merged with the founding X-Man, Jean's telekinetic and telepathic power amplified dramatically. Even though she was originally regarded as the weakest member of the team, fusing with the Phoenix turned her into the most powerful person on the planet.
Jean originally saw the Phoenix as a blessing but it wasn't long before she realised it was a curse. When The Hellfire Club learned of Jean's newfound powers, they tried to use the Phoenix to take over the world. But since the Phoenix can only be tempered by bonding with a specific host, The Hellfire Club placed all of existence into jeopardy when they released the cosmic force from Jean's psyche. Giving into its primal urges, the godlike creature turned Jean into a malevolent being called Dark Phoenix.
Upon her awakening, Dark Phoenix flew into space to find an energy source to feed its power. After she fed from a star in a neighbouring galaxy, it went supernova, wiping out the nearby planet, D'bari IV, killing five billion sentient lifeforms.