The Plutonian is the main villain of the comic book series Irredeemable by Mark Waid. He was a very powerful superhero similar to Superman, who was the Earth's greatest protector but eventually snapped due to all the pressure people put on him, as well as the generally selfish nature of humanity for which they expected him to solve all their problems for them, and became a complete murderous psychopath waging a personal total war on humanity using his godlike powers. He has killed millions of people and destroyed entire cities around the world, and is the single greatest threat to humanity in the universe of the comic. A group of his former superhero friends have joined forces to stop him, but can only hope to defeat the Plutonian if they can find out his weakness and secret identify, which no one else knows. There is also a spinoff series called "Incorruptible" in which the Plutonian's former archenemy from when he was a hero, Max Damage, becomes good in response to the Plutonian becoming evil.
At the end Plutonian was dissolved across universes. He became an inspiration (at least in our world) to creating Superman.