Source: comicvine.gamespot.com

5. Dr. Polaris

Dr. Neal Emerson was a physician who specialized in magnetism, using it to help create miracle cures. Unfortunately, his overexposure to magnets caused him to develop a split personality that manifested itself as the evil Dr. Polaris, a supervillain who used magnetism to commit crimes.

The two personalities battled back and forth for a long time. Then Polaris was approached by the demon Neron during the Underworld Unleashed event. He volunteered to sell Emerson's soul in order to gain more power. Dude was straight up evil. He killed Steel's grandma!!! Who does that?

He also tried to take control of Earth's South Pole like a jerk, and eventually joined Lex Luthor's Secret Society of Evil. In this capacity, he was part of the advance team that went after the Freedom Fighters. During the fight, The Human Bomb unleashed his full power on Polaris, annihilating him.

He was succeeded by John Nichol, before Emerson came back from the dead to rip his heart out. Literally.